Suggest Appropriate Usage Of DermAid Soft Cream

Hi I went to my docter today about a rash I have on and in my vagina. She said that it is most likely a reaction to something. And she told me to get DermAid soft 1% And i was just wondering is it safe to use on my vagina lips, the outside and the inside of the top.??Im just worried cos it says external use only on the box. What do they excatly mean by external/internal??