I would take him to the Dr and mention the smelly wee. My DS had one at about 6 mths old, his fever spiked up to 40 and we took him to hospital because he was so little and they were about to let us go home because they thought it was just a fever, but then checked his wee. If you are TT'ing him it will be a bit easier to "catch" one - we had to use a plastic bag to catch J's and he had to stay in hospital for 2 days on IV antibiotics because he was so young, but at an older age, a normal course of AB's should clear it up. I don't think there is any redness that you can see and they may not have any soreness when doing wee or any other symptoms other than the fever.

Good luck hun xoxox