So, on a thieves guild quest and I had to sneak into a house. I left my follower, Borgakh, outside while I snuck in to plant the stolen necklace. Somehow she ended up inside the house anyway and since I'm not technically supposed to be in there she just tells me I'm not allowed to be there. I can't ask her to follow me, or even to return home. How can I fix this?
Wait 3+ days and she will return to where you found her, or you can try returning to that house during the day - it may only be illegal to trespass there at night.
If you're playing on PC, open the console, click on her, go outside, open console again and type
moveto player, she will be teleported to you.
Lastly, you can try befriending the owner of the house by doing their quests, though that only works with some NPCs.