I think you should stop using the Nivea to jelq with.
I would go with KY Jelly and keep a bowl of warm water near by to dip your finger tips into to keep it really slick. With the water dip, you will not have to add any more KY other then the initial application. I use about two, 1 inch gobs to get going.
If you want to go oil based, I would try the tried and true baby oil.
I am sure the Nivea is a very fine lotion, but it is not the best lubricant, plus it has a lot of ingredients that after rubbing them so deeply into your cock, you may be having a reaction to. So switch to the KY or baby oil and see if that doesn’t solve all your issues, including the swelling.