lol, man, I am in the exact same situation.
I bought 500g dnp a long time ago and since then I have used MANY times and I have also been over 1200mg/day. I freakin love DNP, love what it does to my lipids too. But suddenly I used it and had chapped lips, horrible mouth ulcers and on my penis' skin. I wasn't sure it was dnp's fault, so I tried again and got the same sides again.
I waited a few weeks and tried it again with an anti-histamine and it didn't help.
Now its been some months, so I decided to try it again. I took a 200mg cap today and 20 minutes later I started feeling my lips and penis itching again. I immediately took 3g quercetin + 3g bromelain + 25mg cetirizine. 20 minutes later the sides calmed down and I just took 15mg prednisone.
This time I am 100% sure I am not using dnp again. Too bad, I loved it so much, lol. Do you think it wouldn't have happened if we didn't use high dosages?