How many clear coat stencils did i send you??
 If you have one extra then you can VERY lightly clear the far right bumper area... this will seal what you have done.
Then apply  stencil to the whiote area that needs touching up and very gently DAB some white into the divot.

The clear should prevent any further paint loss when you remove any mask... in fact your Tamiya tape is perfect for this... place a small strip over this litle are and carefully cut the groove where the white needs to be with a scalpel with a fresh blade... doesnt have to be all of the circle... just the bit thats missing and a little further.
Tamiya tape is the most gentle yet best line mask i have found.

This way you can "fill" and retain a clean edge.

Wait till you put the "lacquer" finish over the top and get the same semi gloss as the rest of the PF... this will look fantastic!