Whisker question

Hello!  I'm new to this forum so be nice.  :)  My wonderful Bob is a five or six year old red heeler mix.  I noticed tonight that he has some red (looks like blood but there's nothing wet) right where his chin whiskers meet his chin.  Just teeny tiny- nothing on the fur, just at that pinpoint place where the whisker grows.  I'm planning to call the vet in the morning, but wondering if anyone knows what this might be due to.
 
Thank you in advance!