My fan at back of my electric oven isn’t working and looks like it’s going ?

Probably just needs a new fan and motor (they are often sold together).
the bit you see glowing red is the heating element, not the fan. The element is overheating. You may need a new element as the old one could have well distorted and is now stopping the fan. Both are reasonably simple no jobs for someone competent.
You'll need to know the make and model of your cooker.

Fghhdds
December 2019