I wouldn't worry about. It happens frequently. I think everyone on here that knapps, has had that problem. I had a piece get in my shoe, and then in a VERY hard to reach part of my left big toe. I had to do weird yoga like positioning to even try to get to it. Finally about a year, later, it came to surface enough for me to twist, and contort my body enough to dig at it with a needle, to get it out. I had an old Tryon style single shot muzzle loading shotgun, my Grand father had given me as a child. Not knowing any difference in powders, and pressures, etc. I would load it with 410 shot gun powder, and then put paper wadding in, and then dump in the shot, and then more paper, and then a "Greeney Stickem cap" which was for cap pistols, but it worked for the nipple of this old gun, and it would fire quite well. However, I ran out of old 410 shells, and had my trusty homemade powder horn, into which I had dumped the contents of a couple of M-80's. Sooooooo. I took my trusty powder horn, and proceeded to load the old gun. I had just put the wadding over the steel ball bearing, I was using for a shot, and was putting the stickem cap on, when my Dad came out and asked me what I was doing, and I told him I was going to shoot Grandpa's old gun again, so he stood there watching as I aimed at a tree, 50yds away, and pulled the trigger. KABOOOOOOM!!!!!!!
Well the stock was on the ground, and the barrel was on the ground a few feet away from the stock, with a nice curve to it, and the bottom of the breech was all flared out. Thank God it was the bottom, and not the top. My arm was bleeding, and I had a nice wound on my left forearm, where metal, wood, and other forms of shrapnel went through. My Mother yelled what the hell was that?! My Dad in his ever present lack of tactful way of saying things, said, "Oh Way just blew his arm off. WEll she comes running out, and I ended up at the Doctors office, getting the wound cleaned out, and sewed up. Years after that, I would be sitting in class in High School, and I would notice some black spots, on the scar tissue, so I would squeeze the area, and a splinter would pop out, and I would pull it the rest of the way out. So it may come out sooner, ........ or later.
Epsom Salts is quite useful for many things, and it is good for your sliver. Hydrogen peroxide is excellent also. But eventually it will work itself out.
Wayne