A few months ago my red eared slider got some sort of infection on the right side of its face/head. A big ball of hardened puss formed under the skin in the turtle's head. It was nasty! The infection first started with an eye infection of some sort, shortly after I got the turtle.
I called over my friend who works in a vet's office and she promptly helped the poor thing.
Here are a few before and after pictures.
First is the way the turtle looked,

And an after pic:

The turtle was then treated with antibiotic ointments on the eyes, and around the wound as well as with antibiotic injections, very low dosages. The turlte was kept dry for about 2 weeks, and tweezer fed.
And what it looks like now.
Here it is in its superman pose

And here it is after it saw me.
As you can see, it has completely healed. No furthure infections have appeared in the 3 months or so since the treatment. I'm glad I was able to help it out.