If you're going to run it on the old stud, knock it back down in the hole with a hammer. Put a plain nut on it so you don't bugger up the threads, and tap it down semi-gently until it's close to level with the next one. We did that to a friend's old Camaro years ago, and it not only got him home from Little Rock, it ran fine until the next time he over-revved it and pulled them back out again.
There's a tool for pulling lifters, but I've done it with a small screwdriver and a few choice words, if necessary. If they're not too gummed up, or beaten outward, at the bottom, they usually come out without too much trouble.
If the lifter bottom is dished, your cam is shot.