Some lizards are able to voluntarily detach their own tail as a method of evading predators. This is commonly known as tail dropping, but the technical term for it is caudal autonomy. It is important not to grab or tug on your plated lizard’s tail, as although tail dropping in plated lizards is not as easily triggered as it is in other species (ex: crested geckos), it can and does occasionally happen.
If your plated lizard has dropped its tail, don’t panic. In most cases, special treatment is not necessary and for the most part you can leave the wound alone. However, if you are concerned, swab some betadine or povidone-iodine solution on the wound to disinfect it immediately after the drop.
Plated lizards regrow their tails, and they do so quite well — you may not be able to tell the new tail from the old tail when it’s done!