Don’t have any revenge ideas, but maybe it makes you feel better that shortly before I gave birth to a 10 pound baby, our second child within a year and a half, my HUSBAND told me that I looked like Freddy (Krueger) got me. :(

Mail him a snail-mail envelope of glitter.

Technically, if they bother you, you could diminish them significantly with microneedlying or/and lasers. Would be interesting to ask your dad why he would say something like that and if that's the type of person he really wants to be.

tell your mother... doubt she want to hear about how your father is poking fun about some minor thing caused by having her grand baby. good chance she brings up something about him he is embarrassed about to put him in his place

Tell him from us that he's a ********. And that actually, it's a sign that you're a tigress who's earned her stripes. Then growl a little bit, just enough to make him nervous.

Try Bio-oil. You'll need to use it for a while but it really helps to fade scars and stretch marks.

Tell your dad his receding hairline / bald head is really unsightly, and he should probably do something about it.