Can vaginal thrush cause sores ?

Probably herpes: This sounds you have recently acquired genital herpes. Yeast (thrush) doesn't cause blisters or sores and usually little or no discharge. Get professional care ASAP, the sooner the better (within a day or two) for both accurate diagnosis and effective treatment. If not confident in your GP's expertise in herpes and STDs, visit your nearest NHS GUM clinic for guaranteed expert care. Good luck!