I've had a small pimple-sized, dark pink bump that looks like a bite for several months. It's very itchy. It's on my chest wall. Sometimes there is a second one nearby that comes and goes. I've been putting hydrocortisone cream on it, but it doesn't really help. There is no drainage or pus or white head. If I scratch too hard it bleeds occasionally. No one else in my family has it. Should I go to a dermatologist?