I recently been diagnosed with genital herpes I have a huge open sore on my vaginal lip the doc gave me Valtrex (valacyclovir) but its not helping with the pain I ca?

See your DR. How long? Is this your first herpes or a recurrence? Check with your dr. Maybe something else is wrong.
Pain meds. An acute attack of herpes can be very painful, especially with an open sore. Aside from the tenderness of the sore itself, like any sore anywhere on the body, salty urine will burn and sting. Try urinating in the bath and use a blow dryer rather than toilet paper or a towel to cleanse yourself. Ask your doctor for pain meds. This will pass in about a week and Valtrex (valacyclovir) will help.