I have very sensitive skin (ezcema) so I'm familiar with hives and they SUCK!
I've had laundry detergent give me hives, shampoo, even our water here at the new house, if I stay in the shower too long, I get hives. Must be because the water here is so heavy.

If I'm covered with them, the only thing that helps is an Aveeno bath. They go away like instantly. If it's just a few, I use hydrocortisone cream.
I hope beyond hope that it's a good sign for you!! Whatever you do... DON'T scratch them and then touch a place that has no hives on it... because it soon will! LOL!!