Hi, I have had two bite marks on the outside of my thigh on my right leg. At first I thought it was just two mosquito bites I had got over night. Then, they started bruising in a pattern. After the bruising showed up my leg started itching, itching so much that it began to bleed (and there was never a scab). They feel like there are two hard knots under each of them. Last night I noticed I had a red and purple rash above them. These bites have been on my leg I would say for about 4 weeks and don t seem to be improving. Should I be worried? Do you think this is a spider bite?