Poor Samantha! Gracie has those too on her chest. I'm trying to keep an eye on them.
When we first got Bud, he was chewing his feet like crazy until they bled. We thought he had a thorn or something but he ended up having a food allergy. Anyhow, before we found out about the allergy, the vet thought maybe it was an infection so we had to wrap it up with a baby sock and then put a band of velcro around it. It would have worked pretty well except he chewed the velcro off. After the vet found out it was an allergy we switched his food and he doesn't chew his feet much anymore. Other than that I haven't done much first aid.
I do have an animal first aid kit just in case.