Nail picking and biting problem

I have picked my nails since I was a young child. It had got so bad that I would start at the cuticle and pick my nail off by the layers no matter how badly it hurt me. And it's not all my nails that I would do this too, just my pointer finger and ring finger on both hands. I would always pick and bite other finger nails but only them would I actually hurt myself so badly that they would just bleed and hurt but I would be in like some kind of trance and block everything out until I picked every layer off. These 4 finger nails are deformed forever now.. I have had to ware fake nails for over 20 years now and that is the only way I stop myself but I will still pick at my cuticles.Now my son picks and bites his nails until they bleed and he will also pick at any sort of bump on his skin until it bleeds. I will change his sheets and they will have blood all over them. I say something to our doctors and they blow it off like no big deal but it saddens me to see him do this to himself everyday and I can't seem to help because I'm doing the same thing.