Child Taking Antibiotics After Appendectomy. Has Cough And Cold. How To Protect Wound?

My 9 year old son had an appendoctomy three weeks ago after his appendix ruptured...he was in hospital for twelve days. He is still on antibiotics , which finish in five days ( ciprofloxacin - 500mg bd) but has developed a nasty cough/ cold , which is going around the family..what should I do to protect his wound? He also isnt eating much, which i can understand because he probably feels so rough. He still complains of pain in his tummy, which surprisingly is in and around his belly button and has bouts of bloating , he is going to the toilet fine though. Thank you