our dog smelt really bad when we first got him as he was from a farm and was covered in poo, wee and sawdust we bathed him once and he still smelt we left him for a while to see if he carried on smelling and after a few days he didnt smell NO TCP involved lol

It's difficult to guess from the little info you've given, but my first thought is it sounds like may have irritated his/her skin by washing him too much and/or with something too harsh for doggie skin. What did you use, shampoo maybe? In future you'll want to use something milder. There are doggie shampoos in petshops, etc. but some people use mild baby shampoos.

What did he smell of? If it was a 'doggie' smell then tbh, even after a bath my dog smells doggie, just less(convinced they make the dog shampoo smell like dog, lol). If he smelled of urine, faeces, etc. then he may have been kept in bad conditions before coming to you and that could be a cause of skin irritation too.

Or it could be completely unrelated to either bath/smell. Whatever the cause, I'd recommend taking him to your vet, just to be sure, they'll be able to give him something to stop the itching too.

Without meaning to cause any offence, do you know much about dogs? You mentioned not owning a dog before, if you're feeling a bit lost there's loaaaaadssss of great doggie info online, it's definitely worth doing a bit of researching as there's a few things that aren't obvious if you've never had a dog before.

What kind of dog is he/she? Any pics?

A check up with the vet would be a good idea anyway with a new pup.

The groomers near us do a puppies first bath for free, might be worth seeing if any near you do a similar thing?

You could also rinse your pup in an oat solution (porridge oats in a sock and run the water through it) which may help soothe the skin (and smells quite good too)

Not sure I've heard anyone refer to their puppy as "it".

You need to take your puppy to the vets ASAP for a full check up. You should do this within a day or two of bringing a puppy home regardless.

Also, what's she fed on? Rupert absolutely reeked on the low quality stuff like Bakers, Wagg, Pedigree etc but didn't smell anywhere near as bad on high quality foods.

I'd second what others have said though, vet check.