You should take your child to see a doctor as soon as you can make an appointment. It's possible that your child has strep throat. If that's the case, your doctor can identify the illness and prescribe some medicine which will make your child feel better very soon.
Fever in children can be more dangerous than in an adult. If a child, especially an infant, has a fever they should be taken to the doctor to be checked. Sores on the throat could be a simple sore throat or strep throat. The latter would require an antibiotic.
Take your child to the doctor, urgent care facility or emergency room. It is quite possible that he has strep throat, which is serious and highly contagious.
If your has a fever and a sore throat then give him an over the counter fever reducer. Some warm tea with honey will help his sore throat, but also have him gargle with salt water. If the fever isn't better by the 3rd day please call your doctor.