Hairs not growing back after stitches, in moustache area. What can I do? (Photo)

Wounds and scars need a year. To completely heal and contract. Once this is passed,it can be seen what it looks like and what needs to be done. If there is a gap, the scar can be re used removing the scar and suturing the skin closer together, decreasing the area. Should hair actually be missing, FUT transplantation can readily be performed to reconstruct the area.

After a wound or a scar (having stitches) there will likely be local hair loss.  This hair loss is in most cases permanent. 

I always advise patients to wait 6 months to let the area heal and see how much regeneration of hair will occur in the area. Then you can proceed with either hair transplantation into the area or scalp micropigmentation (SMP).

Produced an area where there is no hair. This can be treated with either a hair transplant or scalp micropigmentation (see web reference below)

It is common for a trauma such that you had to induce a temporary hairloss called shock loss. The majority of the hair regrow after four months and if hair does not grow in a small portion,  you can have a few hair grafts transplanted to it.