It's not a word. Out of curiosity, where did you see it? The word may have been "welled" which would mean, basically, that the wound was filled with blood. Similar to saying, "Her eyes welled up with tears."

I think you mean welled up= filled or was swollen

Thanks for your encouragement. Actually, I'm just reading the excerpt about the combat between Beowulf and Grendel. It is really difficult to understand. So I do some research about the epic on line. My research helps me understand the excerpt much better.

You're quoting from "Beowulf," aren't you? If that's the only line you don't understand, then you're a genius!