Your coin looks to have areas of lamination showing mainly on the reverse. Note the lines running North-West to South-East through the metal of the coin. This is quite common on the 35% Silver Jefferson
War Nickels due to improper mixture and impurities found in the silver alloy. It can look like cracks or splits in the surface of the coin and in extreme cases it can split and fold or drop off of the coin completely. When it does split off it can leave a rough pitted looking area that may show weak or blurry devices struck deep into the coin.
The area that's raised on your coin is the lamination pulling away from the rest of the coin. In mint condition this might be worth saving as a planchet error. In this condition it's most likely only worth the melt value of 95¢, but scrap buyers tend to pay a little less for
War Nickels as it's harder to reclaim the silver.