One breast is larger after upsizing - what could be causing this? (photos)

It’s hard to know why your right breast is so much bigger.
You should probably get a valuated and be seen by your surgeon.
Perhaps doing an ultrasound can help determine if there’s a possible fluid collection.
I will say that as a general statement anytime excessively large implants are used the chance of undesirable side effects, complications and need for revision surgery will always go up.
The bigger the implant the more likely it is patient will have complications and need more surgery.
Something to consider.
Best,
Mats Hagstrom MD