I made myself a 750ml pot of tea, put it on my desk beside my bed and it jumped off and covered my foot and bed in boiling hot tea. The red ring has 2 blisters inside and the purple ring is the whole area of redness. It is incredibly difficult not to pop the blister, but I'm not going to.
I asked a pharmacist what to do and I'm now the proud owner of some antibacterial cream, wound pads and bandages.