If you have acne, opting to seek professional help can be a tough judgement call. After all, there are countless brilliant resources online (ahem) where you can get the lowdown on powerfulย DIY or topical treatments.

But what about when yourย questions go beyond the typical โ€œWill these breakoutsย ever go away?โ€ When you find a mole in an unexpected colorโ€”or a tiny, mysteriousย bump (โ€œWhat is that?โ€)โ€”it may be time to seeย an MD.

โ€œThere are three main types of skin cancer: basal cell carcinoma, squamous cell carcinoma, and malignant melanoma,โ€ says Arielle Kauvar, MD, a New York City-based dermatologist and founding director of New York Laser and Skin Care. โ€œEach type has different appearances, butย they have early warning signsย you can watch out for.โ€

Of course, you may not be checking every square inch of your body on a daily basisย (which is fine)โ€”but Dr. Kauvar saysย the American Academy of Dermatology recommends that youย do self-exams at least once a month. โ€œThis is especially so if you have a lot of moles or freckles, or if you have a family history of skin issues,โ€ she says.

The majority of the time, these conditions stem from sun exposure. โ€œOver 95 percent of basal and squamous cell melanoma are caused by the sun,โ€ she says. โ€œMelanoma, on the other hand, has a 20 percent risk for areas that donโ€™t ever see the sunโ€”it can be inherited.โ€