8 Month old White English Bull Terrier Skin and lots of problems! Any advice please..?

Hi all. My Eng bull is 8 month old he has been biting his tail due to glands being ful, they were emptied and he has stopped biting his tail to baldness!..The vet also put him on Steroids, a small dose, 8 a day for 2 weeks. He is a little 'under the weather' and grumpy/growly with me, but ok with my other dog-playing with him etc. He now has a skin infection ( Redness,spotty,puss) by his private parts, which I have been given antibioyics for him, for 2 weeks... Can anyone with experience of eng bulls give me any advice on looking after Wilsons skin.I always take him to the vets when there is any problem, but feel I get fobbed off with tablets etc. Thanks