I found someone online who has a rat kinda sorta like mine.

http://ansbrook.co.uk/ansbrook/Rat%20Gallery.htm if you look at the rats named Stephanie and AshLee, the smaller one has "extra color" (for lack of better words). looks kinda like a hooded but with siamese markings. where mine looks kinda like a siamese/capped.

do you think it could have anything to do with the deworming? the stuff was called droncit. it was injected between the shoulder blades, not way up by the top of her head tho, so I guess that wouldn't make any sense.

i will keep my eyes on her, it might just be something fluky that she will shed out. but so far the spot on her head seems to be getting darker as she ages.

PS
im very interested to know if any of your siamese/hemmy ratties have this. let me know when ya get the chance