My SandyMan is becoming cat reactive Please Help!

[Teresa2091]

Hello everyone, I have an 8 month old chow chow/ pit bull/ shar pei mix male he is a reddish fawn color! He has lived with cats his entire life, I brought him home a day before he turned 5 weeks old. I know 5 weeks is extremely and way to early to leave the mother and siblings but if you would have seen him you would have paid an extra 55 bucks on the spot for him as well!! A woman had seen my interest in a dog on a FB rescue page and commented she had chow mix puppies. I really had no interest in purchasing a dog from someone because they could be either A. puppy mill B. back yard breeder or C. random w/e. So I was skeptical at first and asked for info and pictures and why she had puppies in the first place. Rescue is a very serious thing for me and I absolutely hate unnecessary breeding! She said her female 7 year old chow chow must have gotten out of her fencing one day because she heard some random noise outside so she went out to see what her dog was doing and well her dog was giving birth to puppies in a dirt hole she had dug on the side of the fencing. Instantly my heart dropped and I became a little attached right their, I probably should have just ended conversation their but I was interested. She brought the mom dog inside and our puppy who was born first in a dirt hole and set her up in a crate to have the rest of her pups. Apparently she stopped feeding the pups at two weeks so that is when they started eating hard food and had been playing with a 2 and 5 year old little boy and girl since birth. I asked her if I could see the one born first who was suppose to be all white at the time, she said no problem and we could meet at tops in her town. So we met at tops and her she pulls out a shoebox with this little itty bitty puppy inside, he was just laying their not doing much. I pulled him out and that's when I started noticing the problems: he was covered in huge huge huge black/purpleish fleas (they looked ready to explode), his white fur was a yellowish brown from urine and feces, he was thin but extremely large in the belly area so I immediately assumed worms, and the fact he was not active worried me a little as well! So I paid her an extra 55 dollars on top of the 100 I already had discussed with her. But after I paid her and he was in my vehicle I took him straight to my trusted vet where he was fit in for an emergency apt. He was 5 pounds, filled to the brim with worms (of course), has an extreme flea allergy (which is now finally under control), and several skin issues. It has been 8 months and we are just finally getting to the bottom of his skin issues and psychological chewing of himself issues! Hopefully soon he won't have to wear a cone all the time and can resist the urge to chew even tho their is no reason to chew or rather no apparent reason to chew. He eats a no grain diet Taste of the Wild. Finally we are out of the woods with all of that, but recently he has been becoming more and more cat reactive not aggressive but more reactive. He is 56 pounds and growing so you can imagine what it is like for him to come barreling into a room and try and full body slam pounce a cat. I have two personal and two foster cats that I have had for up to 6 years so being cat reactive cannot happen! I need advice before he gets too bad and hurts one of them!!!