You have done a pretty good job of describing this issue. You realized the sensitivity was better when you abstained, so recognize that climaxing can bring about a more sensitive state. It also causes your desire to increase. I would cherish and explore them as nice feelings after climax, being gentle instead of rough.
As for your penis, it sounds like chaffing and perhaps Balanitis, which both can occur from the actions you have described. If you are going to grind, I suggest eliminating all cloth contact especially jeans. Chaffing aside, you can also have issues from chemicals in the fabric.
Smelling is a different story. You need to nail this down and clean it up. Perhaps it is the fact that you ejaculate in your cloths and then do not wash, or just leak all day from excitement and you need to bathe more often, but if this is after a good scrub in the shower, you should visit your doctor.