Yes, and possibly a little quicker, if there is the beginning of the scabbing process, the crusty collegen formation and dried serous fluid, then they may not stitch either but that does not happen in 2 or 3 hours if you have a deep scalp laceration, and no medical person is going to release someone without a lot of documentation if there is a possibility of head trauma, since that can present much later....a good bop on the head, even one that doesn't knock you out is usually a one way ticket to hospital for a cat scan, and some tests, and most often observation.