Fold, and fold fast. If you don't injury your wrist as you quickly fold your 8s, you're not mucking fast enough. Based on your post, the only reason you 3-bet was to isolate the aggressive UTG+1 player. Unfortunately, you didn't succeed, and you didn't connect all that well with the flop. You need runner-runner for a str8 or one of the two remaining 8s to likely have a chance. You still have 2 players left to act: A wild player who will likely raise, and an old lady who was willing to call after a raise, a reraise, AND a re-reraise. Based on your position, the fact that you didn't hit the flop, and your statement that "not many pots were being 3-bet preflop" but this one was capped," your 8s are almost guaranteed to be a huge dog. Remember, your original intent for being in the hand was to isolate against a loose player to your right. However, this didn't work. Throw in the towel and save your chips; there will be other hands.