Im allergic to ticks. When i get a tick, the reaction i get is an ichy rash all over my body.. To get rid of it i need to take antibiotics and use a cream. I havent ever had anything similar to what you are describing though, so in my experience i would tend to think they are due to a different reason. You can get scabs even though you dont bleed if the skin has been broken. If it looks infected, just try and put some anticeptic or something on it and keep it clean. And just keep an eye on it. If it looks to get worse or he seems to feel a bit off, then maybe a trip to the doctor.