Back from the vets with a rather grumpy Pip. Ity looks like he either has mites or may have had them at some point and the area has got infected. The area under his arms is bright red (you can't see it in the pic) and it looks like he's scratched it raw.
He's now on Baytril, some drops to kill any remaining mites and some drops to soothe the itching. He squeaked all the way thruogh the vets and squeaked when I did the drops just now so I'm just going to let him relax a bit now.
Poor little guy has had a stressful day