How long after crown lengthening procedure can a crown be put in?

after a crown lengthening procedure, the provisional crown doesn't fit at all, and it doesn't hold there. Considering a healing period is needed after the crown lengthening, is it a good idea to put in another provisional crown less than three weeks after the crown lengthening procedure? My dentist says the tooth cannot be uncovered, and strongly urges a provisional put in right now. I'm not sure if more healing time should pass before a provisional crown is put in.