Well, if you suffer with rosacea it could well be that. Especially as it can be aggrevated by skin products.
I assume have treatment for it?
Does it come up as you shave or after you use post shave products?
Other than considering the rosacea and trying to isolate any products that do / don't affect your skin I would suggest the usual advice:
Keep yourself well hydrated
Ensure you face is well soaked/hydrated before shaving
Use as little pressure as possible
Don't push for BBS shaves (it only grows back anyway)
Maybe use 1 less pass
Give your face a good cold soak post shave
Let us know how you get on..