What Causes Itchiness In The Vulva And Brown Vaginal Discharge?

Wondered if anyone could be of help. In the past few days my vulva came sore and itchy due. I put this down as being due to wearing pads with tight fitting pants on a really hot day. These developed into sores that constantly itch and are painful, especially when urinating. I visited my GP who initially thought I had herpes, but upon examination said they are most likely friction burns or symptoms of thrush, despite having no discharge. The doctor prescribed me Clotrimazole and this is slightly decreasing the itchiness. I also pulled too hard on the skin when applying the cream and my glitoral clan has come out of the hood. I m worried this may be something other than thrush. However, I did have a gaeynocology appointment last week prior to the development of the sores and he said all was well. I just hear so many horror stories! So, my questions are does anyone know how long this is going to take to heal? At work as a Healthcare Assistant I wear tight black trousers but cannot find any looser. I ve also began to experience a brown like discharge with tissue like substances in. What can I do with my clitoral glad? Many thanks!