Im 16 and noticed a pimple like bump under my eye/eyelashes its been there for a while its rlly small it doesnt hurt but what is it?

Stye or chalazion ?: Could be a hordeolum (stye) or chalazion( blocked oil gland). Both are usually just observed if small. Warm compresses might help if it's a stye. Hard to tell without seeing it.

Stye: It sounds like a clogged eye gland called a stye. These styes can be painful and and when it calms down can become a cyst. If it is small and just started use Johnsons and Johnsons baby shampoo to clean your lashes, eye lids and use a heated towel for warm compresses every 15 minutes for 3-4 days. Then get rechecked by your doctor.

?: Could be a stye or a chalazion. A stye is painful so I doubt you have one. Have it checked by your primary care doctor who may or may not send you to an ophthalmologist.Good luck.