Black crust in sternum

[Higor]

Sorry for the bad english,
Some days ago I noticed this black solid spot in the sternum (like a crust) after seeing her scrat it all night. The other day I notice a white spot in the opistosom with the same black dot in the middle. Opinions? I swear thats not a tumor and thinks thats some type of fungus.
now she in dry and medicate the interested part with betadine 10%.
Suggestions are really appreciate, thanks.

 

[viper69]

Could be anything- just leave it and wait