Gynecomastia has two types (silly me took years to notice):
1) Pseudo , just fat which can be removed with exercise/lipo
2) Gland / breast tissue, this one will stay forever unless surgically removed (I exercised till I can see my abs but still there) you can squeeze it, if it is some lump/tissue, most likely it is going to stay.

You may refer to the video here (a lil bloody but it gives you an idea what is hiding underneath your puffy nipple):
https://www.youtube.com/watch?v=1sLkuFmp3KY

Mine is #2 one side / unilateral, got mine done below 4k @ Dr Cheong You Wei, Cheras in about an hour time. Still recovering. If you have some spare cash, do check him out. Usually he does not charge consultation fees and most of the treatments are very affordable.