Don't stress if someone doesn't post right away. Just means no one with the answer posted.
IMHO, you're pooched. This exemplifies the use of a clean environment and judicious use of a tack cloth to ensure a clean surface before application.
For most, you'll have to live with the blemish.
There are a few things that can help alleviate the worst but none come without a price to pay. In all, patience is a virtue. Do the work without interruptions. Kick the kids and spouse out of the house, set the phone on silent and leave a note on the door that you've died and you won't be returning.
Use a razor blade or a brand new X-acto blade to cut a very small slit as close as you can to the particle. Try to follow an existing edge in the art if you can. Don't cut the decal at an angle but straight down, then use the tip (X-acto is excellent for this) to "hook" the edge and lift. Cutting at an angle creates a wider profile where there won't be any adhesive on the edge. That edge
will lift over time. Carefully hook the particle and pull it out. Gently push the "flap" back down. If you "touch" the adhesive too much, it loses its grip and will likely open up over time. Don't be tempted to use super glue to seal the edge, it's too difficult to do "just enough."
Don't be tempted to cut across the debris. The risk of a messy edge when putting it back together is too much and if the debris explodes as you cut across, you'll never get it cleaned out.
If it's an air bubble, (did you use the wet application method? No? Shame

) steal one of your wife's sewing needles and punch a hole dead center of the bubble. Squeeze the air out.
If it's hair, leave it. I have eight hair producing animals and three human females in the house. The amount of hair that's produced is atrocious. That ---steaming pile of meadow muffin--- gets everywhere. The only real solution is to use copious amounts of fluid to "wash" the hair away
before application.
Don't squish the debris down. That doesn't work 99% of the time. You'll have the debris pop up over time and you'll likely mar the art trying to get it flattened.