Ectropion in young patients can result from aggressive skin removal, post op bleeding/hematoma, abnormal healing. Lubricate the eye. If this does not respond to conservative treatment such as taping, massage, injections. Surgical revision is indicated by a very experienced surgeon.
This is a possible complication of lower eyelid blepharoplasty and is called a lower eyelid ectropion. If the lower eyelid is not anchored adequately or correctly during the time of the procedure, the lower eyelid may droop downward leading to an ectropion. I would recommend frequent lubrication to the eye to prevent your eye from drying out. During the day, I would recommend using preservative-free lubricating drops (any brand is ok) at least four times a day (more if needed) and lubricating ointment inside the eye at bedtime. If the ectropion does not improve, the best method to correct this issue is with surgery, where the lower eyelid is tightly anchored. In the meantime, it is best to keep the eye lubricated.
You have some ectropion from the surgery, with the skin pulling the lid down and out. At 28 days you would hope to see some improvement in this. Warm compresses and massage may help. You might also benefit from some injections into the lid if any scar bands can be felt. If this does not correct you will need a revision. See an oculoplastic surgeon for this.
The use of a subciliary (just below the eyelashes) transcutaneous lower eyelid surgery has the greatest risk for the eyelid retraction you are seeing. The treatment you have been recommended including taping it upwards and massages can help. Certain injections can also help depending on how the wound feels. If this fails to improve then a tightening procedure can be done. It is important to continue to follow up closely with your surgeon to make sure this resolves because if left untreated it can cause eye problems.
I hope this helps and good luck.
You do have lower eyelid ectropion/retraction, which unfortunately can happen after transcutaneous lower blepharoplasty. There are scar injections that can help. Massaging and squinting exercises are also useful. If it persists after 3 months, may need to consider lower eyelid ectropion/retraction surgery. See an oculoplastic surgeon.
Massage and taping are a good start for now.
Also squeeze the eyes shut to activate your closing muscles.
More work may be needed later, but starting with this is best for this stage of healing.