after I masturbated I noticed a lump in side the skin of my penis but it went away what does this mean
Hello,
Since the lump has been painless and present for a couple of weeks, so either it can be a cyst or a benign skin growth. They may occur anywhere on body but scalp, ears, back, face, and upper arm, are common sites for sebaceous cysts. Blocked sebaceous glands, swollen hair follicles and excessive testosterone production will cause such cysts.
Generally no treatment is required but they become painful then it means they are infected, then surgical excision may be required. Also if turns in brownish lump then wart has to be ruled out and if it scabs, then herpetic blisters has to be evaluated.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.