Thank you very much for the useful information Jeremy.
Most likely this is "Stye" which is a condition in which there infection of the base of eye lashes.
Since the lid is also some what swollen, it seems that there is also ongoing inflammation and this needs to be treated at earliest.
You would require a clinical examination and prescription drugs (antibiotics) most probably to treat this so do not delay an appointment with the eye doctor ASAP.
At home following measures will help.
Washing the eye frequently with ample amount of water.
Use optivar or acular eye drops to control the irritation, itching as well as swelling.
Oral ibuprofen will help reduce not only the pain but also its anti-inflammatory effect will reduce the swelling.
Keep yourself adequately hydrated and get this examined/evaluated soon so that a specific and targeted management plan is instituted that suits best to your needs.
I would have been worried too if I were at your place, but let me reassure you that this does not sound serious at all. It is a treatable condition and carries a good prognosis with appropriate management.
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