It makes no difference to the effect of the healing whether you are participating in it at the time it takes place or looking back afterwards. Each body is in a different dimension (reality) and only the dimension on earth knows time.
During a healing you work with energy, which has a vibrational frequency. And based on frequencies you can connect. So the effect of the healing is the same whether you are physically present or not.
When doing a healing, it is important to do it in a protected space (healing space), with the right tooling (healing techniques) and the expertise needed to do so (healing spirits and angels).
What you feel during a healing is person-dependent and varies from one healing to another. Some people get very tired, while others feel hot or cold. If it is an intense healing, you may have sore muscles or feel sluggish for several days.
Everyone carries patterns, beliefs and thoughts that keep you from being fully yourself. Through healings you can neutralize and remove these.
A healing is a reprogramming of your energy system and separation of energies. It gently frees you from obstructive (behavioral) patterns, beliefs and thoughts.