I haven't ever done this, but I have seen chipped markers repaired by mixing some abalone dust with CA glue, filling the chip and sanding smooth. The dust is really bad for you though, and new marker dots are cheap, so probably easier, cheaper and safer to just replace it.
Others with more experience may have a better idea
#001 (LP-1S) [finished - co-runner up Nov 2018 GOTM]
#002 (WL-1)
#003 (MPL Megacaster - semi scratch build) [finished]
#004 (ST-1 JR - Arachnoid Superhero build) [finished]
#005 (LP jr)
#006 (TL-1A)
Junk shop acoustic refurbs (various)
'The TGS Special'