If you are referring to what the teacher said to me. "You do not have enough Compassion for yourself," it normally means there's a lot of self judgment, perhaps even a rejection of our ability to open to our Dukkha.
Sometimes it can manifest in the tendency to separate ourselves from the rest of humanity, feeling we do not deserve compassion, yet others do. We may not accept our humanness and expect a lot from ourselves.
There may be a harsh type of mindfulness based in a lot of effort to become an ideal, rather than opening to the suffering or problems that this particular person has in the present moment. The person may feel that if they become their ideal then they will be worthy and okay.
Other times they allow themselves to be swayed by others, doing things they know will cause suffering to themselves because they don't have the strength or confidence to say no.
So to have Compassion for oneself is very important, in order to change the intention. It is helpful to use the Four Noble Truths as a moment-to-moment practice, rather than having a goal orientated practice of wishing to reach the ideal or the total end of Dukkha in the future.
In this way we are more able to open to any Dukkha arising in the practice, feel compassion for it, see the true cause of it and let it go in the present. Then our intentions are transformed into the wish to heal. The Compassionate intention becomes the key to letting go.