I love two creams I get at my local health food store, Sssting Stop, and Florasone. Between them, I can quickly handle just about any kind of bite, itch or rash without toxic ingredients or side effects.
I hope you'll avoid Deet compounds on your little guy. There are alternatives. I was really excited about a recent suggestion to add a little vanilla extract to water and spritz it on to keep mosquitoes away. I'm sorry to say that at least on one local strain of mosquitoes, it hasn't worked for me. I've actually gotten more bites.
I have found another non-toxic product called Neem Oil to be effective in stopping insect damage in the garden, and I hear that it also keeps mosquitoes away. I'll be trying that next, myself. It's so safe that people in India (where the neem tree grows) have used if for centuries to brush their teeth.
Skin So Soft is said to be very effective. I personally get ill from the strong scent, and can't be around other people who are using it. But it's probably a better option than getting bitten. Especially since West Nile virus has begun showing up on this side of the ocean.