

This is most likely not linked in any way to your sexual partner. What you are going to need to do is give your penis a complete rest and let the damage to the area heal naturally - this could take anywhere between 8 to 12 days to 3 to 4 months so that the necessary healing is complete.
So, no masturbation as what this may have started as is a slight bit of damage to the skin in the area and with the friction and pressure due to the penis being erect on a regular basis, the skin has simply broken-down even further.
That is, with the frequency of masturbation you are not enabling the natural healing process to begin and proceed to a normal conclusion.
Depending on the level of damage it is possible you may need to get something like a steroid ointment to help this to heal - but best let it heal naturally - if you give it a complete sex and masturbation rest you should know whether this is going to heal itself within 12 weeks. For most cases, 3 to 4 weeks rest should be sufficient …