Suggest Remedy For Red, Spotty And Itchy Cheeks While Having Dry Skin And Eczema

Hi
My son has had a dry face and escema over his body these last few weeks. We have had him on antibiotics for staph infection which we finished the course about New Year...he is getting a few more infected areas at the moment, and just this morning we have put some Foban cream on the couple of pussy areas...He had a bath this morning and we applied the normal cream that we use to his face....which is the Cetamacrogol CR BP. this doesnt usually cause any problem on his skin.....but a red spotty itch has come up on his face, so I quickly gave him some histafen. It seems to have helped. He felt pretty hot this morning....he is a hot boy, and once had a large heat rash come up all over his body after sleeping in a sleeping bag one night....What do you think is the cause of all this skin problems?? Im pretty close to getting an allergy test done on Charlie, but most of the time the dry patches are manageable so I keep forgetting to pursue the cause!

His right cheek has just come out a bit red and spotty, which is very itchy. So I have just given him some histafen...as it looked like an allergy reaction. His skin is so sensitive at the moment to anything we are putting on him....but we have to keep moisterising him etc. Plus its summer over here, so we need to keep the suncream up to him aswell....its a real juggling act.
The Histafen seems to have stopped the itch on his face. What would have caused this quick reaction??
Thanks
Amanda Withers