I'm guessing our narrator was changing the dressing on whatever wound that started out as, and freaked when she saw it had turned black and seepy. She filmed herself attacking it so the vet would have a video record of her freaking the fuck out.
And I cannot stress this enough, but that is one very long-suffering dog.
That's very impressive. Not as impressive as the (sadly removed) http://www.poetv.com/video.php?vid=11935 , but still very impressive.
And the fact that it's a video being sent to someone she loves, for them to 'get a kick out of' really takes the cake. The chunky cake with 'currants' and creamy mauve-taupe icing.