Toy fox terrier with sore, red front leg

Question
Our toy fox terrier has a front leg that is very sore and dark red in color.  We are quite worried about him.  He does not seem to favor the leg at all, but if I touch it or press on it, he yelps.  About a month ago he had a terrible dark purple area of bruising on his chest and under his arm that took weeks to heal.  My husband thinks he is crawling under the fence and hurting his leg in the process--he is a definite escape artist.  I don't know what, if anything I should do for this.  Is just watching it safe or does he need to go to the vet?  Our finances are rather strained at the moment, or I would immediately take him, but we will go if it is urgent, no matter what.  He is 12 years old but still a very energetic and healthy dog otherwise.

Answer
Maybe you can put chicken wire or wood around the bottom of the fence to prevent him from going under, keep the area clean, make sure he does not chew on it, wipe with peroxide and watch for any infection. If your dogs starts getting any other symptoms take him to the vet. Sincerely, Angela