Small scraggly spot(groove) on surface

After released the deck from mold, I found a small scraggly spot on the deck side, length is about 3inch, 1inch wide, 18mils depth. I want to repair it with some gelcoat but I worried about color difference. :!: So I did some sanding and polish, now it's better but still not perfect.
Any guys has better idea
Also how to repair the mold

 

Since you molded the part do have any of the same gelcoat ? (HOW TO repair the part not the mold)

1. Sand with 180g in the area of the defect
2. Sand with 400 g 2 inches out from the defect
3. use a metal ruler as a straight edge and make sure you have sanded down 12 to 15 thousand in the 180 grit sanded area and maybee 6 to 8 thousands in the 400 grit area with an even taper.
4. fill the defect with colored gelcoat and light filler or polyester putty
5. Spary gel coat only on the 180 sanded area 2 coats then spray a 3rd and 4thin coat over all out to the 400 grit area. It really helps to use Duratec Highgloss Clear for the final 2 coats reduced down 50% with your matched color gelcoat, it sparys well and allows an air inhibit cure
(So no wax or PVA needed with the Duratec additive) other wise mist a little PVA over the patch maybe 1/2 hour after the last coat was applied

 

If you have any gel coat problems and any repairs on Boat or mould post pictures !! Those you sent the other time were perfect and every onewas able to see what was there . Answers were a little confusing but one picture is worth a thousand words .