Try a fan brush or increase your pain tolerance or use a less-pigmented blush.
I adore Plum Foolery! Can you use a stippling brush, wipe off more excess than usual and sweep across your face without it being uncomfortable? It can show up dark on me too (NW20) and I apply it with my 187 but only use the smallest amount and then build up gradually if needed. Other alternative would be to apply a light amount of face powder over your blush to lighten the colour but not so much to look cakey?