Empathy is toddlers?

So I have a 15 month old boy. Today I cut my hand and had to wear a bandaid on it. My son saw it and became curious so I told him it hurt and that it was a boo boo. He seemed really interested in it and so I showed him the cut. Then I told him I was ok and I smiled and kissed it and all that. Moments after he became noticeably sad and worried. Tears, quivering lower lip, etc. He also wanted to hug me and kind of just sit with me.

Is it possible for little ones to feel empathy like this? How does he know what a cut is? Or what blood is? He's never been cut or seen me or my wife have a scrape or anything like that. I was a bit touched at first but then started thinking it was a bit weird, that it was possible he had been exposed to something like this before. Like, he had seen other scrapes or cuts before at daycare or something. Hopefully he was just worried about his dad. Seems kinda wild to me, though, that he could sense it, or just knew it hurt or whatever.

Anybody experience this before? Or can shed some light on this one?