I recently underwent PDT with Levulan (60 min) and Blu-U (9 mins) for back acne. Why does my skin not feel burned or appear red?
Skin Didn't Respond to PDT for Back Acne
Doctor Answers 1
Need a longer incubation time
I think you need a longer incubation time (ie let the product sit on your back for longer) as well as possibly more time under the blue light.
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