Nursing strike 9 month old

My previously boob loving 9.5 month old (bottle refuser, up several times in the night to comfort suck back to sleep) has gone on nursing strike since around midnight last night. We saw a nurse this afternoon who said he has hand foot and mouth so am guessing his mouth is too sore to latch. He cries and bites if he comes near my breasts. He's taking some EBM from a cup (fridge cold!) but not a 'full feed', some sips of water and some soft solids. He's also gone off being fed with a spoon so my DH suggested it might be the act of opening his mouth wide that hurts.
I've been expressing at his usual feed times to protect my supply and trying him on the boob with no pressure. He's also been having regular painkillers. Anyone else been in a similar situation and have any tips? I've been so upset today, am not ready to stop!