Is it OK to trim the skin beneath your nail?

i have a habit of biting my nails and sometimes i bite at the skin. if it's dead i bite it off but i don't like naw at it if it's not because that would make it bleed and hurt and it could get infected. basically if it's dead and hanging off i bite it off. and if it's not i leave it alone. by the way, way to not text me back last night...jerk!