5 months post. Why is there a gap at the corner of outer eyelid and eyeball after lower blepharoplasty? Will it heal?

Need photos and examination to better help you. You might be referring to lower eyelid ectropion or retraction. Treatment could be just more time vs revision eyelid surgery. Personal consultation is needed.

You have an ectroprion which unfortunately the revisional surgery did not successfully correct.  Each surgical procedure results in more scar and repeated procedures before the healing process has fully resolved (which takes 8-12 months) can aggravate the scarring process that resulted in the ectroprion.  At this point you need to wait 8-12 months and then likely will need another corrective procedure which may very well be more involved than the revision you have already undergone.

This is what I advised you originally: You have bilateral lower eyelid ectropion after lower blepharoplasty.    Unfortunately, this is unlikely to heal to a normal appearance. You would benefit from active management for this.  If your surgeon is not receptive (and often they are not) you will benefit from active management of this by an oculoplastic surgeon.  Do not let your surgeon hustle you immediately back into surgery for a "tuck." This often just uses up resources need to definitely fix the lower eyelid.  For now it is best to manage the eyelid with conservative measures.  If the eyelids are not satisfactory in 4 to 6 months, then revisional surgery is available to restore the appearance of the eyes.

It is best to garner an opinion only after a thorough exam by a qualified surgeon.  One needs to evaluate if the lid is lax or is the lid being pulled down by scar tissue. 

Pictures and most importantly a physical exam would be needed to determine the healing of an eyelid revision.  The eyelid heals very well in general and has an excellent blood supply.  Generally plastic surgeons who perform high volume surgery are able to estimate wound healing and guide expectations accurately.