My 3.5Years Son Has 3~4 Lumps in His Neck

Sounds like swollen lymph nodes - part of the body's defense system against infections. The nodes exist in clusters so it's not surprising that your child has more than one lump. If your child has been sick several times, they can be and remain enlarged. They can be tender to the touch. This happened to me - I was worried too but the doctor explained it to me and it went away. Usually it's nothing, especially if no other problems exist such as elevated blood levels. However, that doesn't mean to ignore it and not keep an eye on things, or to consult the physician again. You can also strengthen your child's immune system - that's what I did, and none of us has had a "sick visit" in 5 years.

Lymph nodes fight infection. Swelling is a sign that his body is doing what it's supposed to do.
Swollen lymph nodes can stay swollen.
This is not the best place for medical opinions/advice.
Best to talk to his doc if you're concerned.
Good luck!

The lumps are probably his lymph nodes that are still swollen due to the infection he had. It is fairly normal for lymph nodes in some people to remain swollen for a time even after most symptoms of an illness seem to be gone. When you say "child specialist," I hope you mean a pediatrician -- right? If your son has no other issues, wait. If the swelling remains after another week or two, ask to see the doctor again. This sounds like normal recovery from a severe cold. But don't hesitate to ask questions of your doctor.

When they get sick (cold, cough, fever, infection) they will get swollen glands in their necks, and in some cases it can take months or even years for them to go back down. It is usually nothing to be concerned about.

If my child had those lumps and the doctor told me it was because of a previous cold, I would not leave the office until I had an understanding of how long to expect the lumps to remain, what to be looking to happen as it returns to normal, what to be looking for in case it is something else and I need to bring my child back.

If you feel you have any unanswered questions (sometimes we think of questions later), call the doctor's office and ask. It's never too late to ask!

Probably swollen lymph nodes. Rey common in children. These little ones like to keep us on our toes.