Will my hair return? I had 3800 FUE grafts 10 days ago

You may have been over-harvested, and if that is the case, it may not return to normal. Wait it out for six months and see what happens. If your donor density was low, this can happen and cause donor site depletion, not only where it is outlined, but throughout the donor area as well. I am particularly disturbed that the hair loss occurred on the upper part of your donor area near the fringe where the hair may not be permanent.

See here:  https://baldingblog.com/2017/07/21/many-fue-grafts-many-fues-grafts-one-know-safe-limits/