There is a vain under my eye that has been visible for as long as i can remember. also, i can't make a fist. is that bad?

2 different issues!: Presence or absence of veins varies from person to person. As long as it hasn't changed, it's probably not an issue. But if it worries/bothers you, go see your FamilyDoc, perhaps a Dermatologist who can offer different laser options to minimize appearance of vein. Regarding your inability to make a fist, we need much more info. How long? Pain? Preceding injury/trauma? Numbness tingling weakness?

Probably unrelated : Single Prominent veins on or around the eye are usually just variations of normal. However, if there are multiples of prominent veins and/or if there is bulging of The eye it may be something more serious. At your age it is probably a variant of normal, especially if there are no other signs. Likely the vein is not related to your inability to make a fist. See a doctor for further clarification.