Should I be concerned?

This was on my fuzzie's stomach for a few days. This morning I found it scratched off in the hammock she sleeps in and was wondering if this is something that I should be concerned about? I heard something about Adrenal Disease and am seriously hoping this isn't it. I know this isn't dirt or something because there is dried blood where the scab used to be. I know there is no substitute for a vet, and will take her if necessary. I just need an opinion on what to do next, or if there is anything i should be watching for.