I seemingly mutilate the nail and nailbed of my toes regularly.
Excessive picking/biting of the nails often leads to the nails chipping and tearing, or even having whole sections removed, leading to lots of bleeding.
I don't feel much pain from it though. Also, you'd be surprised at how much blood can come out of the nailbed of your little toes.
And through picking I've also given myself in-grown toenails before. (When I pick them they grow back curved, which makes it possible for ingrowing. If you cut your nails, always cut them straight across.)
And both my big toenails and my thumbnails have had large yellow/green blisters full of pus grow on them before, due to infection caused by having the nailbed exposed.
They never hurt, but they did have to be burst before. It corrodes some amount of the nail too.
Most of my fingernails are fine though now, since I avoid picking them too much, since the damage caused to them can make it impossible to do some things, due to the pain with them. Particularly if I damage the thumbnail and the nail of the index fingers.
My toenails are a bit of a mess though.
I'm mostly surprised that I haven't ruined them so much that I've had to have them surgically removed, which is common.
If you remove the nail from the very base of itself (where it goes under the skin) it will never regrow.
