Is my hair finally regrowing after 2 years of wait ?

Hello, i pulled 80% of my hair in 2017, i was almost bald, and it was two times...2 years after, my hair never regrowth like my real hair.
It is still damaged, my density is at a low percentage, maybe 70/100% from my density of before.
I started taking a complex of vitamines, like Zinc, B9 and a lot more...It’s been 1,5 months/1,5 since i took this.
I saw something very strange happening with my hair ! When my hair is oily, i can see some black dots under my scalp...In my hair hole on my scalp there is only one single hair ! And some are thin and some are thick ! In the single hair hole, i can see a black dot ! Is this an hair that is regrowing under my scalp ? I don’t see all the time the black dots, it’s only when my scalp is oily or very oily...My hair seems to get back it’s density ! Is my hair regrowing ? Can someone help me ? It seems like this hair was sleeping under my scalp, is this the return to the anagen phase ? How long it takes for the babies hair to be on the scalp ? Thanks !