Have a sore on my labia minora looks kind of like a blood blister. hurts when touched. how long should i monitor before i see a doctor? possible dx?

You need an exam: It is important with these symptoms that you schedule a visit for testing. This sounds like you may be having a herpes outbreak. It can cause blisters or areas that feel like cuts surrounded by itching or burning. Certainly other things are possible like an infected hair follicle, a small abrasion and others. Don't wait. Schedule a visit.