I have period blood on my pants.
Why do you bring up something like that?
It's there because I had my period.
Having blood on your clothes for any reason can be disconcerting to others, so if it happens during your period, you should carry a change of clothes, or at least, be ready to wash your clothes before you go back out in public.  There are also period products that can help to prevent these mishaps from happening in the first place.
I'm now aware of that, but it's too late for that now! Next time, I'll definitely be prepared!
Maybe you can find a friend or family member who can help you out now and next time you'll be prepared so it won't happen again!