Hello , Only Sixteen And Iv Been Having A Sore

Hello , only sixteen and iv been having a sore buttocks for awhile know. iv noticed theirs a small lump on near my bumhole area its not visible to the eye but can be felt. once felt it feels like loose skin and also tighter near the middle, this is extremely sore when I move and sit and I have to use a cream named anusal ( which is used for piles normals) to smooth the soreness and redness but I also want to now what isit but dont want to see my gp about it as I find is embarrassing.