I’ve used Emla cream, now known as Elamax for probably 7 years on my 3 kids with no problems.   There are a lot of good natural oils to put on the skin for rashes, etc.  Tea Tree Oil is excellent but does have a drying effect which may not be good for your rash.  I make a balm with Shea butter, Jojoba Oil, Almond Oil, Vit E with a dash of Peppermint Oil.  Its great on my children’s exema (sp?) patches!