Could be a maturing hairline forming. Could be the way you’re parting it.
I would be careful asking questions such as these to a bunch of strangers, particularly in a highly neurotic, anxious and insecure environment such as a hair loss forum.
before you go down the rabbit hole of madness, take a deep breath and read everything here with a grain of salt. Don’t make the same mistake many others make. These hair loss forums are addictive as it only fuels your anxiety, keeping it alive.
get the info you need and get the f*** out of here. Preferably, go to a dermatologist if you are SERIOUSLY concerned.
final note about propecia: I can say with all certainty PFS (permanent side effects) exist. I’ll get flamed and downvoted for it, but f*** it - I’ve done more research than them. However, I don’t intend to get into a debate about it because I really don’t care about changing people’s dissonant beliefs.
anyway, have a good day OP. Keep a level head.