Swap faces or expressions

Swap a smiling expression from one frame into another for a corporate profile: replace Sam's closed-mouth expression in photo B with his smiling expression from photo A, then deliver the final to HR and to Sam for signoff by Thursday. Ensure lighting and skin texture match, maintain natural eye direction, and preserve the original file's 16-bit depth before export.

Before I present the face-swap to the client, make it seamless: match the jawline shadow, align cheek highlights, straighten the crop so the eyes match angle, and check for registration artifacts around the hairline and glasses. Flag anything that will look fake on a 300-pixel-tall profile image and note where a reshoot would have been faster.

I just grafted Sam's smile from one take into another and on 100% view the hairline and ear edge look displaced. I'm worried the client will spot it and accuse me of sloppy compositing. I don't know whether to redo the swap, attempt a hair-by-hair repair, or request a reshoot. What's the likeliest quick fix to restore believability and what do I tell Sam now?

I keep getting requests to swap expressions at the end of retouching and it adds hours to delivery and raises suspicion about authenticity. What routine or client-facing rule should I adopt so swaps are either planned into the shoot or limited to fixes that won't trigger extra rounds of approval?