The redness, swelling, and heat in one ear may be due to mosquito bites, especially in the summer months. There is also a case of acute auricular chondromyelitis, where the child may be repeatedly pressing one ear while sleeping. In this case, it is necessary to actively apply antibiotics to reduce inflammation, preferably cefuroxime sodium injection, which can reduce inflammation and swelling quickly. There is also a case of bacterial infection of the ear, often caused by contact with sewage, or unclean hands often scratching the ear, in which case you can apply topical Bactrim cream on the surface of the ear, which can effectively anti-inflammatory and reduce swelling.