My tongue is swollen and i have veins engorged underneath. is it normal?

May be normal anatom: Large veins are not uncommon under the tongue. To check out your veins requires someone with experience to look at you--usually a dentist.

Allergy: It sounds like a local irritation or allergy.

Normal: The under side of the tongue normally has bulging veins. If you never looked at it closely it may look abnormal. See your dentist or an ENT to make sure it is not out of the ordinary.