Ugh. Omg. Not the entire tooth but where it's receded. I've OPed a few times and this morning i looked at my teeth in the mirror and this area of several teeth are very very dark! YIKES! Is this temporary? I'm gonna try swishing w/ hydrogen proxide. Anyone else have this happen? (I'm using 1 tbs. olive w/ 2-3 drops of neem 10 - 20 min.