4 months post op chalazion surgery. Eyelid shape has changed. What surgery do I need to go back to normal? (photos)

You have hollow sunken left upper eyelid which may be improved with upper eyelid filler injection. There could another issue. Best to see an oculoplastic specialist. 

I would not recommend doing any surgery for the eyelids for at least a year.It may be that you would benefit from anchor blepharoplasty with a small ptosis correct. Finding very precisely eyelid plastic surgery is very challenging. 

Thank you for your question and photo. Regarding the shape of your eye, it is unfortunately hard to predict whether it will return to normal or if there is anything to be done without examining you in person and knowing how your procedure was performed. I would recommend seeing your surgeon to be evaluated. Regarding your loss of eyelashes, there is a chance that they will grow back. While it is annoying, I hope it might put your mind at ease you to know that I tell patients that madarosis (loss of eyelashes) is a risk both of surgery to remove a chalazion and of not doing surgery and leaving the chalazion, so this could have happened either way. Hope this helps. 
Dan Landmann, MD, MSEE