Im 18. left eye swollen over period of a week. hurts to blink no known bites, no allergies. no makeup used other then mascara *new bottle. what now?

Allergic reaction: Most likely you have a senstivity to the new mascara. Stop using that tube and avoid all eye makeup until your eye is better. If your eye itself is painful or your vision is blurry, see MD ASAP. If it is just your lid that is swollen and painful, you can try cool compresses 2-3x/day and take an oral antihistamine, such as diphenhydramine, for a few days. Always use hypo-allergenic eye makeup.

Foreign body : You May have a foreign body under your upper lid. This is the most common cause for your symptoms. You should see an Ophthalmologist, so that he/she can look under your lid.