Looks like a cud… not sure it’s going to add much value though. A more knowledgeable member on foreign coin values is needed for that.
It is not visible in the image but some die is missing in this side exactly opposite to the other side where the cud like design is present.
A cud is a chunk of metal that broke from the die face. The look is a blob of metal that is raised higher than the details of the coin and has no definition. When the reverse is struck it leaves an area opposite the cud with minimal detail, if any, depending how big the cud is on the opposite side.