I think my sister used her breast milk to cure my pinkeye
You said that you thought your sister used her breast milk to cure your pinkeye. Is that the case?
Yes, I took a sip because I thought it would help cure my eyes. She didn't tell me what it was, though.
I do not think she should have done that to you. There is no telling how that could have affected you.
It saved me a trip to the doctors and got me into bed an extra day.
Regardless, your sister shouldn't be giving you things like that without telling you. Besides, you don't know what cured the pinkeye.