Chickenpox in toddler

My son (2 years old) started getting blisters all over his body a couple days ago, the local GP has closed due to coronavirus so I went to the pharmacy, they gave us some paracetamol and this white lotion to put on his skin.

Last night he wouldn't sleep, he was burning up with a fever, difficulties breathing due to this too, put his ribs weren't sucking in, his temperature was 37.6 C. This morning his blisters are absolutely everywhere, it made his morning poop very painful he screamed, it's also in his mouth that his refusing to eat anything so I tried a milk bottle, no luck with that either, the lotion makes him scream and run away from me terrified.

Idk what I should do, is there any way I could make this a little easier for him?

Anything I can do at home because we're in self isolation?

My son is up to date on all his vaccinations, but in the UK they don't offer chickenpox vaccinations to kids