<human>: Okay this fuck up just happened a few hours ago and I'm doing this on mobile so the format will be a little weird

This weekend I'm going to Vegas and I needed someone to watch my dog so my grandmother volunteered to take care of her until I got back. 
So this morning I took my dog over to her house and I sat on the couch to chat with my grandmother for a little while (as grandmas always want to do) and my dog hopped up to sit next to me. 
Okay so I had no clue that my dog must've just freshly taken a shit because when I got up to leave and my dog got off the couch, I noticed a brown spot on the red couch.... I leaned down to investigate and sure enough it was dog shit that was smeared all over and into the couch cushion. 
I had no clue what to do so I just told my grandma I had to leave so I didn't hit traffic (ended up doing so anyway-- instant karma) and just got the fuck out of her house. 
I'm at my hotel on the Las Vegas strip and she hasn't called me or anything so I guess she either hasn't seen (or smelled) the shit yet, or just didn't know where it came from and cleaned it up. 
 
Sorry Grammy, I fucked up.

Can you give me the gist of the text in a nutshell?
<bot>: didn't know my dog had shit on her butt, shit got on my grandmother's couch and I just noped out of there