The medical term for this is Ankyloglossia. This is when the little flap of tissue under the tongue (the frenulum) is attached a little to far up the front of the tongue. This does not allow the tongue to stick out far enough. In mild cases, there is no problem. In more severe cases, the tight tongue makes it difficult to nurse, and might give the end of the tongue a “heart” shape. This problem is often recognized by a lactation consultant when helping a difficult nurser. When done early (in the first month of life or so), it is very easy to fix. Simply clipping the flap with a blunt-nose scissor will do the trick. No anesthesia needed when it is a thin flap of tissue, takes 5-10 minutes in the office and it won’t bleed. The hard part is finding a doctor who understands this problem and will perform the procedure. Most lactation consultants will know of a local doctor that is comfortable doing this.
After a few months, the frenulum thickens and will bleed if cut. By this time the procedure is more complicated and should be done by an ENT surgeon under general anesthesia unless they are much older and can hold still. Usually by this time, the feeding difficulty has been worked out (usually mom has given up on breastfeeding and is using the bottle) so the next concern is speech difficulties during the child’s preschool years. Trying to perform this procedure on a 5 year old is pretty much impossible without general anesthesia, so I don’t recommend it unless there is significant speech difficulty. If there are no speech problems, but just a funny looking tongue, I usually recommend waiting until the child can hold still for the procedure, usually age 10 or above.
So, bottom line: It is possible that the frenulum is still thin enough to be simply clipped. I would try to find a doctor right now who can give you an opinion, maybe a lactation consultant can help. If it is too late to be done without anesthesia, then it is not an urgent matter (unless there is feeding difficulty) and it would be wise to wait until the child is older and is at lower risk of problems from general anesthesia.