Please see if anything persists , these things can be a great cause of concern but nothing significant or alarming , stop monitoring your symptoms and relax as nothing get torn due to this and it’s unlikely to be blood or anything major , though not sure that that black accumulation can be as the details are vague . So relax and stop worrying and check back if you experience any pain or worsening in couple of days
Next Steps
Relax and stop worrying about the symptoms , observe and revert if the problems persist