A healthy 2 yr old toddler won't just break out in an acnerash for no reason, especially since he is much to young for real acne.
So, the question becomes: is it a viral rash (like hand-foot-mouth disease), is it a skin infection (like folliculitis), or is it an allergic or drug reaction? To figure this out, a doctor will have to look at the rash. Meanwhile, if itchy, some oral Benadryl (diphenhydramine) can help.
Would you like to video or text chat with me?