John, sometimes I have been using the original color (like white here), but as you have white and metal there is a risk of bleed onto the metal when using white, so some (gloss) clear is the best option here I think.

Looking forward to see the masks coming off the nose!

Looks like an interaction between the different paints, my friend @johnb. Whatever the cause, you definitely need to sand and repaint. If I can see well from the pic, the paint hasn't cracked near the edges, where the demarcating tape is. If so, you might be able to carefully sand the rest (cracked) areas and repaint, so you will not have to ruin the already painted area underneath the tape, thus saving much effort. Though I have no experience with acrylics, before repainting, I would recommend a light coat of primer, so you will minimize the risk of re-cracking.

Sadly some interaction between the clear and black. Strange as it is the same brand you used for both. Fingers crossed for the re-paint @johnb.

@airbum, @stephen-w-towle, thanks for the feedback. So, sanding it will be.

Looks like your remedial actions proceed excellently, my friend @johnb! Primer looks well applied.

Looks like good remedial work there, @johnb, fingers crossed the black will work this time.

I do hope the fix is a good one John!

What a drag John @johnb but it looks like that’s a good fix.