If you installed it yourself & you have no other option - here's a method you might try (not guaranteed!)
You can cut out the damaged plank by cutting with a circular saw. (You'll need to screw a piece of wood or something onto the bottom of the saw so you can set the depth to be really shallow (however thick the lasminate is - 1/8 inch?)) Cut the plank INSIDE the seams - that is, don't cut right on the seam because you don't want to damage the adjacent planks. Cut as close to the edge as you can, but don't go over. When the cuts are made, you should be able to lift out the old plank. You'll probably have to clean up the edges of the remaining planks using a chisel, utility knife, file ... whatever works. Again, don't damage the surrounding planks.
You won't be able to use the tongue & groove with the replacement plank... so don't bother trying to clean out the grooves from the remaining floor planks. You'll also need to cut off the tongues from the plank you will use to replace the plank you took out.
Now - lay the new plank in to see how it fits. Hopefully, it fits perfectly. Take it back out (& make adjustments if needed.) How are you going to make it stay in place? Again, this is not a guaranteed method ... get some tagboard or better yet, a sheet of formica. Cut it into managable pieces that you can slide underneath the existing floor planks. Apply glue to them and slide them halfway underneath the existing floor (in the center of the hole left by the plank you removed.) Also apply glue to the edges of all of the planks involved. Use your finger or a popsicle stick to work the glue into the wood. Apply to both the existing floor and the replacement plank. Then drop the replacement plank into place. Wipe off any glue that oozed out. You'll have to position weights in various places to make sure all of the edges are even until the glue is dry. (You could probably use tape to help hold the edges down also.)