Hypertrichosis describes hair growth in unusual places, ie. your forehead. I also highly doubt any hair will grow that fast for you to be noticeable after merely 3 weeks.
Either way, the hair growth induced by minoxidil is somewhat curious. People use it for facial hair growth and keep their additional beard gains even after discontinuing the drug but the same cannot be said about scalp hair. No idea about hair in other places tbh but I'd wager it's the same as for facial hair?