What to do in this situation?

This is the first time I am in this situation and after hearing siimilar stories from talking with other sitters I still wasnt convinced I would be in the same situation. A recent client is trying to say her dog got bitten while she was with me. Only my dog and another dog who I keep regularly was here. None of the dogs played with each other and kept to themselves which is normal. Most of my host dogs are spoiled rotten and really laid back like my dog is. I had two meet and greets with this client. Prior to the second meet and greet she had used other sitters and said they did not work out either. However, both times the meet and greets went smoothly. I also make it known that I have tons of random bones around for dogs to chew on. She failed to mention her dog does not chew on hard bones or treats. So of course her dog went to town on the antler bone she found and didn't want to part with it. I took her to a local park and when we came home she ran straight to the bone again. She ended up cutting the side of her mouth and bleed a little which has happened before with my old dog when she started having teeth problems. The next day she was leaving and I showed her owner where she was in pain and bleeding a little. She checked her out and left. Later that night she wrote me and said she was acting abnormal and taking her to the vet. So 3 days after she left my home she went to the vet for a checkup and was cleared. Vet said she was fine. Then I get another message a few days later and she says she was bleeding a little from her neck area and her hair was coming out and made it seem like I lied about the situation. So now her second checkup was today and the vet now says it looks like a dog bite but nothing serious. I've had dogs all my life. Is it just me or does something seem off? Has anyone on here had a similar situation happen?