Have moved the thread for you Rach.

Sorry I can't help with the rash... there seem to be so many rashes that babies get which can't be explained, and are usually put down to a 'viral' rash...
Aidyn developed a rash one week after his MMR, but he was on AB's at the time as well, so we have no idea whether either of those factors was a cause, or if it was related to something else...

I do hope it goes away soon though, and that Milo is feeling heaps better.