We characterize the flow of time with respect to entropy where energy is going from an unstable state to a stable state. Basically from high energy to low energy. Would this mean any particle or anything that goes from a lower energy state to higher energy state experiences reverse entropy and thus time reversal? What would the particle experience as such if it's an isolated system and is going against the second law of thermodynamics and observing everything else?
Basically from high energy to low energy.
You seem to misunderstand what energy and entropy are. Let me try to explain.
The energy of any closed system is constant, and can never change unless it interacts with its surroundings. However, the energy can be distributed in different ways if there is more than one particle.
Entropy is, informally, a measure of how distributed energy is in a system of many particles. For example, a hot cup of tea standing on a cold table has low entropy, but the entropy increases as the heat energy spreads from the hot tea to the table until they are the same temperature.
There are more ways of distributing a fixed amount of energy among all the particles, than having it concentrated in a few particles. Therefore finding all the energy in a few particles is very unlikely; it is very likely that the energy will become more distributed as time goes on. This is the basis of entropy 'always' increasing with time (in human-size systems there are so many particles that the probability of entropy noticeably decreasing is astronomically small).
What would the particle experience as such if it's an isolated system and is going against the second law of thermodynamics and observing everything else?
The entropy of a single particle is undefined (at least in classical mechanics, I don't know how entropy is defined in quantum), since it is related to the distribution of energy.
Since the 2nd law of thermodynamics is a statistical law, though, it doesn't always have to hold. In other words, it is theoretically possible to carefully set up a closed system so that the entropy increases: for example, if you had really really tiny pincers, you could place all the air molecules in a room so that, when you let them go, they all fly towards one side of the room, and all collide with one single molecule, giving it all their kinetic energy for a brief moment. The entropy of only one molecule carrying all the energy is astronomically low, so the entropy of this closed system initially decreases. However, after that the particles will continue to move and collide chaotically, and the entropy will eventually increase again. The problem is this is practically impossible to do on that scale, and the motion of molecules in real life is practically random. Therefore the statistical laws of thermodynamics give an excellent description of the behaviour of gases, and other processes involving large amounts of matter.