My 2 year old has been running a fever since last night his body is hot but he wants to be covered in blankets.can i make this fever worse?

No: The fever itself won't hurt your child. What is important is that you make him feel more comfortable at this time so keeping warm in blankets is a good idea. You can also give him medication such as Acetaminophen or Ibuprofen to bring the fever down. If this fever continues for 3 or more days you should bring him to the doctor to identify the infection and a possible treatment.