What Does A Blood Blister On Penis Indicate?

I just received some fairly vigorous oral sex and afterward, notice a red blood blister the size of my pinky nail on the top of my penis head and a smaller, darker red blister on the side of my penis head. There is no pain whatsoever and it looks like the larger red one has popped and some blood came out. Is this cause for concern and how long should I wait before engaging in oral sex again? Thanks.