My 6 month old learned how to pull his self up he fell and hit his head I don't see any bumps but he has a few red spots that look like blood under sc?

Head Injury. This was a bump from a position of sitting and is unlikely to cause a bad injury. Observe his behavior and follow his usual routine. The red spots are likely the beginnings of a bruise. Risk factors would be a loss of consciousness and/or repeated vomiting. Have him seen for any concerns. All the best.