[Question] What is the best way to let out the bust in Sewing Machines Parts and Sales in Los Angeles

I recently bought this gorgeous silk velvet dress from a thrift shop. Normally I’m not one for mangling vintage goods, but I simply adore it and I’m crushed it doesn’t fit me.

It has a centre back zip and will zip up until the waist and then I cannot zip it up anymore as my bust does not have the same measurements as my waist by a long shot, haha. I possibly need like two inches of room at the top to accommodate the extra boobage I have.

I unpicked the zip to the waist because I saw it had a huge seam allowance and then.. Fuck. The velvet was crushed at the seam it was folded over for the zip so even if it was enough to let out I’d have some ugly crushed velvet lines going in a v-shape down my back. I thought about adding v-shape gussets under the arms but the whole bodice has metal boning and is fully lined so I’m not even sure how possible that is. Worst of all is that there is bloody piping all across the top edge of the dress that I would have to ruin to add underarm gussets.

Any suggestions? I’m pretty stumped.