After waxing my underarm became red. when the redness fades, i'm left with a darker underarm . what should i do?

Reaction: Your skin is reacting to either irritation or there is an allergy to the substance you're using. After the inflammation wears off, some pigmentation changes follow. You should try another method of axillary hair removal.

Diagnosis first: Hi, it’s hard to say without a picture but there is a great app that may be able to help you get a diagnosis without being seen in person by a dermatologist. The app is called VisualDX and is one of the best, if not the best out there. Many clinicians, including myself, use it. Just snap a photo and it gives you a list of possible diagnoses. Good luck!