What to do here?

[Berge20]

Low limit NL game

A couple limpers around and the SB checks. Before BB has a chance to act, dealer begins to burn and turns over the first flop card. Simultaneously (and without seeing the card), BB announced raise and the dealer catches himself w/o exposing any more cards. The BB did not specify an amount, just that he would raise. What is the correct procedure for the situation?

Does the exposed card get shuffled back into the remaining deck and the flop is re-delt after action is completed?

Is the exposed card simply considered as a burn card for the turn?

Does the exposed card actually somehow still remain coming up on the flop?