How long should rest before resuming singing after quadruple-wisdom teeth removal?

When you feel ok: The removal of wisdom teeth can vary greatly in difficulty and thus the recovery time can vary greatly. You should be able to resume singing as soon as you feel ok. (assuming you knew how to sing prior to the removal ! ).

A few days: Normally, after a few days, the gum tissue has healed over the extraction sites & you'll be pretty comfortable. If there's still a little swelling, it might not feel all that great to sing. In either case, you can use your own judgement & do whatever's comfortable. Just stop as soon as you get sore or your jaw gets tired. Each new day will be a little better. You should have no long-term problems.

As son as you can : You can start singing again when you feel comfortable enough to sing. There may be some tenderness in the muscles and singing will be a good way to stretch the muscles and help them heal. Just use common sense and don't overdo it.