You know how to apply sunscreen the right way: Slather on a full ounce to cover your whole body before heading out in sun, and reapply every 2 hours. But are you sure you’re really getting it everywhere it needs to go?

No matter how diligent you are with your sun protection, little lapses can leave certain spots vulnerable to sun damage and even skin cancer. “Not surprisingly, some of the most commonly overlooked areas when it comes to sunscreen are also the areas at highest risk for skin cancer—like the lips, backs of hands, upper back, and the ears,” says Joel Cohen, M.D., a Denver dermatologist who serves on the teaching faculty at the University of Colorado and the University of California, Irvine. These body parts are exposed to the sun almost every day, as opposed to areas that are covered up many months out of the year.

One trick to comprehensive coverage is to use a mirror as your guide. “Before you put on your bathing suit or clothes, stand in front of the bathroom mirror naked and apply your sunscreen,” suggests Amy Wechsler, M.D., a New York City dermatologist and assistant clinical professor of dermatology at SUNY Downstate Medical College. “The visual will help you to not forget spots or assume they’ll be covered by what you’re wearing.” Below are the eight most overlooked trouble zones and tips for protecting them.  

Scalp. If you’re bald or you shave your head, the entire scalp needs sunscreen (and ideally a hat, too). But even those with hair have to be careful. Your part can easily burn, especially if you have fair skin and/or light hair. “I tell my patients to use an oil-free facial sunscreen on their parts because it’ll be the least greasy option for your hair,” Wechsler says.

Ears. Squamous cell cancer occurs frequently on the ears. This type of skin cancer is less aggressive than melanoma—the most deadly type—but can still spread if left unchecked. Any time you apply sunscreen to your face, make sure you use an extra dab to cover your ears as well.

Eyelids. “We often see basal and squamous cell cancers develop on the skin around the eyes,” Cohen says. Because it’s a difficult area to protect with sunscreen (you don’t want to risk getting the lotion in your eyes), Cohen recommends wearing sunglasses with UV-blocking lenses.

Lips. “The lips are one of the highest risk sites for squamous cell cancer,” Cohen says. Cancers that develop in this area have the highest chance of spreading and recurrence, he says. A study published in the Australasian Journal of Dermatology found that 35 percent of squamous cell cancers on the lips return, and the risk of death associated with recurrence could be as high as 15 percent. Many lip balms are rated only SPF 15—which doesn’t offer adequate protection. Just as with your sunscreen, seek out a lip balm with a sun protection factor of 30 or higher and use it at least every 2 hours. And make sure you don’t skimp on balm for your lower lip—researchers from the University of Western Australia found that you’re 12 times more likely to develop cancer there than on the upper one.

Hands. If, like most of us, you tend to wash your hands after you apply sunscreen, the backs of your hands probably end up without any sun protection. In fact, a study published in the Journal of Skin Cancer involving 214 beachgoers found that fewer than half of them applied sunscreen to their hands. So be sure to rub sunscreen onto the backs of your hands, and reapply after washing your hands.

Back of the neck. According to the American Cancer Society, the neck is a high-risk zone for basal and squamous cell cancer. Even if you have long hair, lift it up and cover your neck with sunscreen (you never know when you might sweep your hair up into a ponytail and leave that skin fully exposed). Also, when you wear a hat (you should do so in the sun) be sure it has a wide brim all around. A baseball cap leaves the back of your neck completely uncovered.

Back. Men in particular are at a high risk of developing melanoma on their backs, according to the American Cancer Society. “Not being able to apply sunscreen to this area by yourself leads to some severe burns on the back, which dramatically increases your risk of melanoma,” Cohen says. Experiencing five or more blistering sunburns increases your risk of melanoma by 80 percent and your risk of nonmelanoma skin cancer by 68 percent, according to a 2014 study.

You’ll need help to effectively cover your back with sunscreen. “Even a spray sunscreen needs to be rubbed in,” Wechsler says. “When you just spray and don’t rub it in, you may end up missing large areas.” If you don’t have another set of hands to reach this tricky area, cover skin with a sun protective shirt with an ultraviolet protection factor of 50 or higher. 

Feet. This skin will burn easily if you’re wearing sandals or have bare feet. Apply sunscreen to the tops of your feet before you put your sandals on to ensure that they’re fully protected. This is a good spot for spray sunscreen, as long as you do it correctly. You can’t just stand up and aim downward. The spray needs to be held close to the skin, and you need to rub it in. You’ll regret it if the tops of your feet get burned—especially when you put your shoes back on.