MirMirSquare

Just had the same problem. He complaines "You're not supposed to be here." because you lock picked the door to get in. I took the long way and went through the boilery and the cave. Arriving at his bar he was nice to me and I could sell him my stuff. Then I went to the meadery's door to get outside again. Now I can enter again without lockpicking that keeps him friendly. Maybe the door doesn't remember you're allowed to enter at this time. A disable and enable of the door might help aswell. But I'm not sure. Had the same problem with The Mortar and Pestle in Dawnstar. A few days later I was able to enter normaly again.