What Causes Vaginal Dryness And Skin Cracks?

I am 30 year old female. From time to time I will vaginal dryness and sometimes it will feel like it s so dry it has cracked skin. I am in a monogamous sexually active relationship with my boyfriend of one year. Anyway, the other day it felt dry down there and felt like it had the cracked skin as well but it felt like a mild spat, we began to have sex without lube and I wasn t very wet yet when he just put it in. The next day my dryness and skin cracks felt worse mostly when I urinated. I looked and our sex must ve caused some tearing and a couple of razor burn/chafing like bumps as well. I put some A and D diaper rash ointment down there to soothe and heal the area. Later that day I also shaved and I think I must ve caused some razor burn in the labia area b/c when I put lotion on I felt a couple or small bumps. Anyway, I m not sure if I m asking if I could have herpes or if our rough sex could cause this much tearing and bumps? I have been screened for all STD s as recently as last week with all negative results same as my boyfriend. I don t have any more than 2-3 small pimple like bumps, they don t appear to look like the herpes blisters pictured online at least to me. I have no drainage, pus, itching or burning. Just pain when I urinate due to the acid in my urine going over the tearing.