I am wondering if anyone else's little kidlets have had this?

DD has it and I know the Dr said she will be ok but it's freaking me out. The rash looks terrible and she is happy in herself but man it's stressing me out.

I know there is the minor and major version of this and she appears to have the minor thankfully. I know that major is also "considered"/ can be Stevens-Johnson Syndrome.
Which is in my family.

I guess I am just after reassurance and your experiences.