How to treat burns

It was extremely cold in our house this morning ( literally 80 degrees outside yesterday and this morning was 40) we kept the air on so when we woke up the house was frozen. Sometime today my daughter leaded against the heater and burned her back. She didn’t cry or anything and the only reason I saw it was because I was helping her go to the bathroom. It dosnt seem to bother her, is there something I could put on it or will she be ok?