Be very, very cautious, even if the sneezing has stopped. Pet store pigs are notorious for having URIs, and sadly, I speak from experience. My Mufasa was the most chill little guy you could imagine. He sneezed very rarely, and I noticed hay stuck on his nose like it had been running, but the symptoms were so subtle that I shrugged them off. I was new to guinea pigs and had no idea how quickly they can go downhill. On the night of Day 14 he was very obviously sick and died on the morning of Day 15. If I could do it over again, I would have taken him to my own vet vs. returning him to the pet store as soon as I suspected any problem. URIs are nothing to play with, and although I know some pet stores really do take them to the vet and get them treated during the guarantee period, I would want to be 100 percent SURE.