Welcome to pets. Its hard to tell what is happening on the leg but it does look a little irritated. Have you checked for flea bites?
I am glad your taking the kitty to the vet but I would go sooner than later. It could be painful when your kitty uses the litter box. I would want to have him checked for a urinary infection or possibly even crystals.
I would ditch the dry food and change your kitty over to wet food as soon as possible. It could be the dry kibble causes the issues you may have. Years ago vets used to tell cat owners to feed dry because of dental issues but it is no longer the norm. Wet food will be a healthier choice.
There are many more folks on here with a ton of knowledge that I am sure will chime in to help.
Tabitha April 10, 1995 - August 23, 2013
Bomber April 10, 1995 - July 12, 2010
Winston Nov 15, 1999 - September 15, 2011
Sophie Aug 30, 2011
"UNTIL ONE HAS LOVED AN ANIMAL, PART OF THEIR SOUL REMAINS UNAWAKENED"
He is your friend, your partner, your defender, your dog. You are his life, his love, his leader. He will be yours, faithful and true, to the last beat of his heart. You owe it to him to be worthy of such devotion.