Hit with a baseball lip swollen and little skin from inside upper lip is torn. should i take my son to the er for stitches?

Not necessarily: We generally don't stitch inside the mouth if we can avoid it. The little upper frenum-piece that joins the upper lip to the base of the teeth, is commonly torn in childhood and does not need to be stitched. A big cut with bleeding that wouldn't stop might need stitches, but these tend to get infected if we do & don't if we leave them alone.

Depends on cut: Usually, if the outside lip has a cut with edges that are apart, he can see a doctor, as stitches may be needed. If the outside of the lip has no cut, and only the inside has a cut, he may or may not need stitches. His regular doctor can check, or the er doctor can check, to see how big the inner cut is. A little cut just on the inside of the lip can heal fine without stitches.