Thanks all, I value all your opinions. Wow, that's a name and a half Sqad!
I popped in to a walk in centre and saw a nurse practitioner and she thinks it is an abscess and have given me some flucloxicillin. Hopefully it will clear itself up regardless. I do get a lot of abscesses but usually only in the groin area.
I am on steroids, injection and have been on and off some oral steroids. Not taken methotrexate since early November I think it was but it's not good news as my recurring infections are a pain in relation to being put on the drugs and have already been left until I see them in a couple of weeks without medication until I get better after a run of infections last year then a bad stomach bug before Christmas (norovirus I think, had been going round work).
Managed to get a better picture (trying to retain some modesty!). The redder area around it is all swollen, a bit like when you get a really bad bite and the skin swells up round it. It is really sore. Hopefully this will work.
http://imagizer.imageshack.us/v2/800x600q90/513/aqeo.jpg