My daughter has had mrsa in a severely injured foot, and now 8 years later she has pain and swelling. can it come back?

Can't hide that long: We now find MRSA in > 60 % of outpatient abscesses so it is not as uncommon as some might think. A bacterial infection from 8 years ago is not going to somehow hide & comeback the way some viruses like cold sores do. A new infection could occur with a MRSA staph could happen or it could be a different germ or different process altogether.

One could get : Another MRSA infection, but I do not believe it is the original infection coming back.....That one should of been killed and ended back then. If there was a bone infection though, when treated with antibiotics they could lay dormant in the bone if the infected bone was not excised. And the dormant infection can reawaken say if the foot gets traumatized or something.

Yes: More than likely she has another infection.