help plant problems new growth slow growth

1st grow and its already getting a little complicated lol. Im getting some strange edge burn along the serrated edges on two of the top leaves. purple stems and slight blotchy pigmentation is also going on in the lower older 3 finger leaves (although very small amount and can be somewhat seen...

this baby is in flower and has been for about 2 weeks and the new growth started showing brownish blackish purplish color on one stem now I see it on 3 different stems and it's growing a bit slower now any help please ?