All Intel processors are designed to run at the max speed, with heavy workload, 24/7 without suffering or affecting the performance of the system.
As long as the unit is running within specifications, you should not have any problem.
With instant reaction time of internal over temperature protections it would be basically impossible to have modern CPU damaged by heat even with total failure of cooling.
This old video demonstrates those protections, or lack of them nicely. (AMD was little slower in adding protections)
Only sure CPU killer would be too high voltage by either purposed overvolting or failure in motherboard's CPU VRM or PSU's secondary/output.