I have 2 questions:

1) The USB differential pair D+/D- are impedance-controlled 90 Ohm transmission line..  
Why do I need to put a 22 Ohm series termination resistor in it?
Isn't that a discontinued resistance in the transmission line that could technically cause reflections?  

2) should I implement TVS diodes on USB and I2C data lines?  

Edit: I'm using STM32L152CB-A MCU, the I2C will be user to communicate with some ICs on the PCB itself, and the USB will be used to communicate with a computer which will act as USB host.. I'm using USB2.0.  

Thanks