Does Probiotic Yogurt Help To Treat Buccul Cellulitis?

Hi, my 22month old boy diagnosed with buccul cellulitis on Friday (20thMarch, 2015) & treating with 6.6ml amoxicillin & pain relief syrup tyenalol, he already took 5 dose of antibiotics, yesterday he was doing good but today he was very cranky & continue crying & try to put his finger in his mouth (I think it is itchy). But he doesn t have fever & no warmness over red cheek( affected side) so my question is is it okay Or something serious ? And within how many days the antibiotics will start work ? One more thing his doctor told me to feed him more probiotic yogurt. And 2weeks before he was treated with impetigo