Suggest Treatment For Red Bumps Around The Anus And Vagina

Hello

I would like to have some help with my childs situations.

She is 10 months old, we were traveling for 2 days train and plane and after it we noticed all of a sudden a lot od small red bumps around her vagina and anus, red in color round shape divided iregularly.

We have been to the doctor she prescribed cream and said it could be alergy. We are worried about wrong diagnosys.

Thank you