Dr office fobt negative, dr said i had dry anal area. prior i had exp'd a little bright red blood on stool along with stinging. can dryness be cause?

Could be anal fisure: or hemorrhoid that bled. Unless you have a family history of colon cancer or have had any ongoing issues with anemia or weight loss it's less likely to be occult malignancy or cancer in someone your age. Dryness is not typically a cause. Hard stools and excessive straining can cause tears and bleeding. If it continues discuss further next steps with pcp Consider a GI evaluation as well.