I understand your concern.
In my opinion the blood admixed with mucous discharge might the effect of plan B
Usually there is scope for pregnancy
when semen is ejaculated inside or around the vagina during the fertile period.
Just touching of genitals will not result in pregnancy.
So actually the plan B was not required.
But anyways the bleeding is not related to pregnancy.
The plan B is associated with sideeffects like irregular bleeding ,heavy bleeding during the periods etc.
So the blood admixed with mucus discharge is mostly the effect of plan B.
No need of any intervention it will subside on its own.
Relax.There cannot be any pregnancy.
Hope this helps.