4.2 inches hard? That would be small. Lower range of normal is about 5 inches. 4.2 inches soft? That would prolly be a seven-incher when hard and it's worked well for me for a half century.
OK, the bad news is, an erect penis less than 5 inches is small. The good news is, an erect penis over 2 inches is functional. Now, you say you are past puberty. Are you fully past puberty, or just got some hair recently? You may not have finished growing yet. If you are really worried about it, don't rely on forum boards, go to a urologist who can determine if there is any treatment (hormonal) that may improve your size.
ive been hairy since i was 12 and im middle eastern im very hairy and i have had a deep voice for 2 years and im 6 feet tall
You're only 15. Wait till your 18, then come back and give us an update. In the mean time, here's a link for you. http://www.enlargepenisguide.com/download_videos.htm I've never been determined enough to do it, but I heard it works.
^^ stranger danger, stranger danger run away lol whats with the 10 - 10 year old penis size threads appearing