is plasmage a good treatment for saggy eyelid? (Photo)

Thank you for your question and pictures.  It appears you have slightly hooding on your Upper Eyelids, this extra skin will need to be removed, to open your eye and avoid you looking tired. It can be removed under a local anaesthetic.  The scar is located in the creases of the eyelid therefore fading and becoming almost invisible. 
Upper lid blepharoplasty is a very common cosmetic surgery procedure in the UK. The aim of eyelid surgery is to remove the extra skin giving a fresher appearance. Upper Eyelid surgery causes bruising for approximately 7 days after surgery.  
Please make sure you find a reputable and qualified plastic surgeon who can assess you properly to give you a realistic idea of what outcome you can achieve.  All The Best 

Based on the photo, you have a ptosis on the upper eyelid. This causes the droopy eyelid you see. Upper eyelid blepharoplasty could help get rid of the excess skin and improve the contour of your eyes. Schedule an appointment with a board-certified plastic surgeon of your choice for an in-person examination.