Thank you for the advice.
I gave her a (much needed) warm bath like you said, but aside from a few more bumps, I didn't notice anything else. She's had lice before, but I'm pretty sure they're all gone now, and as for fire ants, I live in the UK and I'm fairly sure we don't have them over here.
I guess I could try giving her some Benadryl, although I'm not too sure on how much I should give her...