Make sure the "flaw" isn't a point of weakness in the yarn. If it's more visual than structural you're not in bad shape.
But examine it closely to see if there's something that could weaken the fabric of your knitted piece and create a hole.
I ran into that very situation and just kept knitting since it wasn't too bad visually. But I checked back after I'd knit the flaw into the piece and saw that it would probably weaken considerably so I ripped back and cut it out, rejoining afterwards.
Better safe than "holey"! :o)