Auto Accident. No Other Vehicles Involved. Should I Still (am I Obligated) to Let Insurance Know?

I borrowed a friends car who had liability on it and ended up having an accident on a divider, no other cars were involved. Now I have comprehensive coverage on my car with mercury with a deductible of $500. In all likelihood this is a total loss.( Air bags deployed, the front wheel burst and the front fender is pretty much backed up until the engine and the car isnt driveable)

Should I just pay him for the car( around 5.3k on KBB) or should I get my insurance involved to see if they will write a check for the difference?

Would my increase in rates justify reporting to insurance(if I dont le

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