How did anyone talk you into a Mullerectomy?
Your eyes don't seem ptotic in the first place and look the same with the phenylephrine test. What was the point of the mullerectomy? Whatever happened to "do no harm"?Having said that, the after photo is most notable for higher lid creases and hollowness which ages you. Not sure what your goal is at this point but some filler injection in the upper lids will restore your lid crease and eyelid appearance.
Revision eyelid surgery
Best to see an oculoplastic surgeon for evaluation. Revision ptosis surgery may be possible. See following link.
I am assuming you just had the left eyelid done, since the right one looks fine pre-op. In the post phenylnephrine photo the left eyelid is still a little low in my opinion, so they would have needed to do an aggressive muellerectomy. At this point I would wait till your out 6 months from the original surgery. If it still has poor contour or height an external levator resection surgery would need to be done. You may want to get a second opinion from an oculoplastic surgeon that is recommended to you in your area.
It is difficult to get a complete picture from Realself posts.
It is interesting that you had a Mullerectomy given what you show as your pre operative appearance. However, the photos you post do indicated an improvement in the upper eyelid position. For that reason, many eyelid surgeons would reasonably believe that the Mullerectomy was an appropriate surgery. It is important to understand that all ptosis surgeries are associated with a failure rate. Most surgeons quote that these surgeries are accurate plus or minus 1 mm. You now have frank ptosis with disinsertion of the levator. It is reasonable to look for revisional surgery. I would wait a full 6 months or more before having this work. You need to very careful pick your next surgeon because the repair for this will be very challenging.
From the before picture it is hard to know why you had a surgery done as you don't appear to have ptosis in that photo, and your lids are lower in the after. I think the contour looks fine in the after. However you have a secondary crease and it looks like some loss of fat. Did they also do external excision? You could have a blepharoplasty to remove the redundant skin and improve the crease. This should at least help with the appearance of the lids.