My Son Having Problem Of Bleeding Throat, Headache , Stomachache, And Vomit

I took my seven year old into the doctors b/c he is a spiker when it comes to fevers and I was having trouble keeping his fever under 103. He was also complaining of a headache , stomachache, and vomited four times. All of which he could have from the fevers. When the doctor was examining his throat she asked what had happened to his tongue. I had no idea, but when I looked over there was blood on his tongue and it looked extra bumpy, especially at middle/back. He said his mouth or throat did not hurt at all. At first we couldn't figure out where the blood was coming from. Then they did a swab for strep. The swabs were coated with blood. It seemed his throat and back of his mouth were bleeding if you touched them. The test was negative and we were told it had to be some kind of virus, to just wait it out and keep the fevers down as much as possible. She did not seem too concerned about the bleeding throat and said she didn't know why it was doing it though. I was wondering if anyone else had ever seen this happen at all?