I pick at my cuticles, i think i damamge my nail!?

I use to bite my nails, and about 3 years ago i stopped, i then picked up on picking on my cuticles. I assume i started it because of something stress or anxiety related. i mess up my cuticles by putting things like a pencil tip or sharp piece of paper in my cuticle and i push back the skin and somtimes the skin tears out, i was doing this and i stabbed through my nail accidentally and left a small cut in my nail, i picked at that and now its a 1cm hole where the white moon/crescent thing is on my nail. im really scared that the nail wont grow back or im prohibiting my cuticles/nail from recovering. can someone PLEASE put me at ease and tell me if my nail will grow back out and that hole i accidentally made will be gone and also how to stop picking at my cuticles. i really appreciate any/ and all answers, thank you so much in advance :D