I am now suffering of swelling and itching lower eyelid for the 2nd time. what are the causes of it? im so worried.

Infection: Most of these are simple for your doc to treat. Reoccurring ones may be an allergic rxn to a staph bacteria naturally occurring in the skin oils at the base of your eye lashes. As a matter of hygiene. Each nite with a qtip or your little finger wash your eyelashes with baby shampoo.

? allergies: Your description sounds like allergies. Try using artificial tears, cool compresses, topical and/or oral allergy meds, and frequent changing of your sheet and pillow cases. If persistent symptoms, you may need to see an eye doctor and allergy specialist.