Your little one is likely ok. I wouldn't imagine there is much aspirin in pepto. I have to take a daily baby aspirin due to a bone marrow condition, and DD's ped says I shouldn't stop nursing, even if the baby has a fever, because the chances of enough aspirin getting into the breastmilk to cause Reyes is just not likely at that dose. So I'd think it'd be similar with pepto.
~Brandon Michael (11/23/03), Jocelyn Lily Nữ (2/4/07, adopted 5/28/07 from Vietnam), Amelia Rylie (1/14/09), & Ryland Josef William (9/7/05-9/7/05 @ 41 wks).