Lump/Puffy throat?

Question
We have a three year old rabbit whom we adopted several weeks ago.  The owner said they thought he was a Californian Rabbit, yet he is full sized and seems small then the breed says they are.  Anyways.  When we got him he was a very playful rabbit that like to run around and play tug of war with a carrot with me.   Then I think he got a cold.  He was a little less playful and had some crust around his nose.  He seemed to recover just fine.  It has been a few weeks now and I am convinced he has a large lump or swollen throat.  It as if it is a round ball just bellow his lip, chin.  I know I could be an "overactive" bunny parent and he could be just fine, it could be his body build.  It just doesn't "feel right" to me and I am not the expert on rabbit body shapes.

Answer
If it looks like a fold of skin right under his chin, it is most likely a "dewlap". Normally these are only found on females, but some males develop them, too. It is normal. However, if it an actual lump or if it is rounded like a ball, it is likely an abscess. In that case, he should see a vet right away. If the abscess has gotten to the size of being able to be easily noticed, the infection is probably spreading.