I got open wounds on outside of my vagina few days b4. But I tested negtv 4 std. So what cause dis? N can I GT break in my vagina skin without std? How

Not STD. There are no stds that have as a primary symptom 'open wounds'. So, yes, the answer to your question is that yes, this is not an std and yes you have a break in your vaginal skin. Skin problems are often fungal, bacterial or are caused by friction or other trauma.