Asked for male, 18 years old from Bangalore
Hi, It's not harmful. It's not unsafe. And it's not risky to swallow your own semen. It's just a natural body fluid like all others including your saliva, gastric acids, urine, etc.
But It Is Disgusting.
I would want to evaluate you for OCD since you r getting this thought repeatedly, it's intrusive and it's against your will. And you seem pretty much in distress coz of this thought.