Well, first of all it CAN be perfectly normal for them to stay a little swollen after their first heat. She could also be having what's called a "false pregnancy" where her body THINKS that she is pregnant and she goes through all the motions (sometimes they even get milk) but there are no actual puppies.
However, I would be worried too that the boarding facility may have let your baby around a male dog. That could be potentially really scary because you would have no idea what breed of dog got her and she could have an array of complications. If I were you I would take her to the vet and have them do a blood test and exam. The longer you wait the worse the situation could become if she IS actually bred. And IF she is I would definitely recommend spaying her ASAP to prevent any complications.
I would be sooo upset with that facility but for future reference I would be careful boarding your girls, except maybe with a family member, when they are in heat. 7-14 days is usually fertile time and male dogs will do ANYTHING to get to a female!
