How Long Until I Can Scuba Dive After Otoplasy?

This is an excellent question and partially depends on how much pressure and what type of gear you are wearing. Part of the problem is that you ears may still be numb and it is difficult for you to assess when there is excessive detrimental pressure on the ear. I would consult your surgeon but it is my general recommendation to avoid this type of activity for 6 weeks.

In general, if all your incisions are healed and there are no open areas, I recommend waiting 4 weeks after surgery.

There is no set number of days that need to pass after an Ear Pinning (Otoplasty) Surgery to make it safe to scuba dive.
Two points.
First, the incisions need to seal and heal somewhat. I would prefer on this account that you wait at least 3-4 weeks. Moreover, all fresh scars are extremely sensitive to the sun's rays. To prevent red scars that would last as long asa year from premature UV light exposure, you will needto wear waterproof high SPF sunblock over all scars.
Finally, the major complication with Otoplasty is recurrence of the lop ear deformity by breakage of the conforming stitches before natural scarring had chance to splint the cartilage in its new bent-closer-to-the-head position. A slap or blow from the back of the ear can cause such breakage or cheese wiring of the stitches through the cartilage. The same can happen when adjusting or taking a scuba mask off. I would advise you to wait at least 2 months for scarring to bolster the repair and even then proceed with caution.
Hope this helps.
Dr. Aldea