Cause of sudden eyelid asymmetry/extra crease on Caucasian eyes? How to follow-up/fix? (Photos)

You might be developing right sided eyelid ptosis.  Without an exam, it will not be possible to fully evaluate you and give you recommendations. I recommend you would start your work up by visiting an ophthalmologist.

Thanks for your question and your photos.  It appears that you may have a mild right sided upper eyelid ptosis.  This can occur from a weakening or stretching/thinning of the muscular insertion in the upper eyelid that is responsible for opening or elevating the lid(levator palpebral superioris).  If this is the case, it can be corrected with surgery.  As you mentioned, there are also medical reasons for this to occur.  The only way to know for certain and to devise a treatment plan is for an in-person consultation.  I would recommend visiting with a board certified oculoplastic or facial plastic surgeon with extensive experience in treatment of the upper eyelid.Best wishes.

For a sudden swelling of one eyelid lasting 10 days, I definitely suggest to see a board certified Oculoplastic surgeon as it could be cause by different factors and needs further evaluation.  

It is normal to not be totally symmetric. We are always our worse critic and this asymmetry is most likely only apparent to you.
Dean Vistnes.
Vistnes Plastic Surgery 
San Francisco Bay Area