For the fever, I can't recommend any PD because it's a Sunday so most of them are closed - but you can continue giving fever meds from KKH if they were opened less than 6 months ago :) To help him, you can continue sponging him, keep him in cool clothes (like shirt and shorts that's not too thick) and let him cuddle/hug as much as he needs! Keeping him hydrated would be important too. As for the rash, you can try Desitin for the diaper rash - but only apply it on the places with rash because it's medicated. It'll also help to clean with a damp washcloth then air dry before changing diapers, and change it more regularly!
I would suggest to continue to sponge your LO and feed him medicine regularly. On top of that, try to feed him porridge water if your LO does not want to drink milk. Monitor the situation. If it doesn't improve, please bring to see a doctor tomorrow! As for diaper rash, would suggest you to use cool boiled water to wash the backside and dry it with towel before applying any diaper cream. Do air the backside with diaper cream for a while before wearing the diaper.
Munchkin Pumpkin