Hello and Welcome! Looks like the dime took a hit and got damaged. "That's all I got to say about that". --Forrest Gump
That's a very important question. One thing I tell new searchers is that not everything that looks different, strange or weird is automatically a mint error. There are many ways a coin can be damaged during circulation and also altered to make it look like an error. It takes time and patience to understand what to look for. True mint errors have been defined and explained. Check out this chapter of this great website. https://www.error-ref.com/part_xi_-_non_errors/ Then look at the rest to get a lot of true mint error information. Mr Ed - Specializing in the collecting of Mint Errors since 1986.
Excellent question...experience will get you there. A way to help is to watch a video on the minting process and you can tell many "errors" could not have occurred during striking.
I believe I can see why you ask about this dime. The "dent" didn't damage the reeding, but did raise the metal in front of it. It just took a hit of some type. The coins, once struck, do fall upon themselves at tremendous speed in the minting process, but I don't believe it is enough to have caused your dime's damage.