I'm going to go a bit against the grain here (hah, no pun intended) and suggest that...

...aside from being very careful with your stropping as was already suggested (only the weight of the blade should keep it on the strop, no downward pressure from your hand)...

...that you also try using room temp to slightly cool water instead of hot during your prep.

I too have a course, fast-growing beard and somewhat sensitive skin (particularly on the neck). My first 2-3 weeks of shaves didn't go too bad - kept seeing noticible improvement. Then all of sudden, instead of going better things started going worse - generating more burn and irritation than previously...

I tried sending my razor to a honemeister fearing my stropping had dulled the edge but still no improvement. Then I suddenly realized that during that same time period two things had happened:
  1. As I gained more confidence my attention got lax and I was using too much pressure
  2. I was focusing MUCH more than I had before on hot water prep - soaking my face with much hotter water in the shower and then again at the sink... and topping it off with warm lather from a scuttle. Not only was it my pores to open and my hairs to lay down flat (encouraging the razor to cut them lengthwise instead of cross-sectionally... it was also softening my skin, 'sensitizing' it, and greatly magnifying the sensations/irriatation it was encountering - much like sunburn turns the normally harmless sensation of a washcloth into firey-hot sandpaper.


When I let off on the pressure things immediately started improving again just the way they had been originally...

And then, the instant I backed off to just tepid or cool water any remaining hint of razor burn on my neck immediately disappeared.

Of course, if you suspect your stropping my have dulled the edge, then that must be taken care of before any these other suggestions have any chance of helping.