I use minoxidil 5% for my hair but it grows hair on my cheeks, front, eyebrows. Is it because I don't cover my head after applying it? Thank you

When you stop using. it, it stops growing hair! So, unless the minoxidil is running down your face while you use it, it should just help locally on your scalp. It won't by itself also increase facial hair. Also the quality of hair is fine and not thick, lustrous hair that is grown. So, if normal facial hair (coarse) is appearing, it may not be because of Minoxidil. See your doctor to examine this for sure.