Allergic to a rat?!?!?! O.o?

I'm very upset because i allowed my brother to keep a rat in my room (Bobby) instead of picking two for myself and just got Albie. They were both really shy when we got them but i worked with albie till he was comfortable with people and thought my brother was doing the same...he wasn't. And as time went on he started complaining about getting them out everyday and about the size of their cage and feeding them until he lost interest in his rat altogether. We got in a disagreement and he said he was going to take bobby out of my room where he lives with his brother and keep him in a hamster cage alone in his room!

So at that point my dad took bobby away from him and said he was in my care now. But the only trouble is that i'm highly allergic to rats that i haven't handled that much, i'm use to handle bobby for a few minutes every day but he was so skittish and now i am trying to get him use to human contact and he will climb on me but when he does he gets scared and digs his nails right in and i get an allergic reaction.

By now the reaction has usually faded where i'd be use to the rat but i thin it's because hes digging his nails in, there not over grown and don't need a trim so i'm at a loss of what to do. If anyone's been in the same situation what did you do. I'm obviously not going to give up on little bobby and i'll handle him every day even if it does mean i have allergic reactions but if there is a way to make it go away then i would loveeee to know.

Thanks in advance