Hello Oregondaisy,
After 8 weeks on the medication, it's unlikely to be a reaction to them as drug allergies usually happen early on within days or two weeks.
That said it is possible that it's a reaction to the medication.
www.aaaai.org/conditions-and-treatments/...g-allergic-reactions
How we proceed depends on lots of things, but primarily this:
Is it getting better, worse, or staying the same?
If it's unrelated then, presuming what caused it was a transient exposure, it should just go away.
If it's related then it would be expected to flare up about 1-2 hours after you take a dose of medication.
It would be sensible to take some antihistamines, but of course, this will mask things.
Some allergies can be life-threatening if they cause problems with swelling of the tongue, in the throat, or with breathing.
Provided things are not too bad a pragmatic approach would be to do this:
1) Take some antihistamines at the maximum recommended dose today and tomorrow
2) Skip 1 days Hep C medication and see if things settle down
3) Depending on how far you are from medical care, how bad the hives are, perhaps park your car in a hospital car park near ER the next day, take the medications, and if nothing has happened 2 hours later go home and continue taking the medication.
The causal agent for allergies can be very hard to track down. I see hives in ER quite frequently and much of the time we don't know what caused it. It is possible it's the medication, so stopping them for 1 day (and presuming the hives settle) testing with re-exposure in a safe environment is a pragmatic way to answer the question.
The preference is to take the full 12 weeks as this will push the cure rate to 95%. After 8 weeks it should still be a 90% cure rate so it's not the end of the world if the medications have to finish.