bump (or lump) on Jack Russell Terriers leg

Question
My one year old JRT has a red lump on his front leg.  He licks it a lot, and it seems to be bothering him more.  I was feeling around it, and he went to bite me, so obviously it is painful.  Any thoughts what it could be?  The bump has been there about a week, or so, and it seems to be getting larger, under the skin around the bump.

Answer
Hi Paula,

Thank you for writing to me.  A red lump that is causing pain and continues to grow for the last week, absolutely must be seen by a medical professional.  Please make an appt with your vet to have this lump looked at.

Best Regards,
Shelley Davis