In the frame of reference of a massive particle itself, it does not experience time dilation. Time dilation is a phenomenon that occurs when comparing the passage of time between different inertial reference frames that are in relative motion. It is the difference in the measurement of time intervals between observers in different frames of reference.
According to the theory of special relativity, as the speed of a massive particle approaches the speed of light, its energy increases, and its time dilation relative to a stationary observer becomes more pronounced. However, from the particle's own perspective, time continues to flow normally, and it does not perceive any change in its own time.
In other words, if you were traveling in a spaceship approaching the speed of light, you would experience time passing normally from your own perspective. It would be the observers in a different reference frame, such as those at rest on Earth, who would observe your time to be dilated or slowed down compared to their own.
So, time dilation is not an intrinsic experience of the accelerating particle itself but rather an observed effect when comparing time measurements between different reference frames in relative motion.