I noticed a red pimple like spot about 2 inchs below my armpit and aout 3 inchs from my breast onthe left side around 3 pm today. It does not itch and only hurt if touched. By around 7 pm it started to look like a small whole, no I did not try to pop it. I tried to keep my arm from touching it because of the pain. Around 8pm it started to burn but the redness was going away. Should I be worried or not? It still hurts if touched.
This could be an infection/ inflammation of the hair follicle/ sebaceous gland. I would suggest keeping the area clean and dry and avoid using external products like talc etc. You may also try antibiotics ointments like erythromycin/ clindamycin. If this does not seem to get better in a week you may consider an evaluation by a primary care physician or a dermatologist for appropriate treatment.
Hope this helps.
Take care!