Very common bruising because the skin layers at the glans were under too high of a pressure after the layers are too softened by the moisture, be water or moist air.
Two options:
First is to stop pumping, and provide warm towel/rice sock wrap, then light jelqs and reverse jelqs to drain the fluid from the layers as many times a days you are comfortable in doing this.
Second is to continue pumping, proving more warm compression in between each session, with jelqs and reverse jelqs to promote blood drainage from all layers. Make sure to ease back the pumping pressure.