How can a person restore the quality of dignity for his or her self?

Let us begin by taking apart the question by looking at its underlying presumptions.

First, "dignity" is a noun, a conceptualization and concretization of an experience, a label--and therefore actually removed from present-time, ongoing experience. As a label, it is shared in language but does not necessarily (and probably doesn't) represent others' experience. Further, the term is a "social" Word, meaning it exists in reference to the supposed thoughts and experience of others; the need to meet an imagined social standard is itself suspect.

Second, where do you suppose qualities come from? Are not qualities attributions that we ourselves lend to the things we perceive?

Third, how do you know that restoring is necessary? What is your test to know that something has been lost? If you can still think of that something, is it not still resident in your experience, by that one test alone (i.e., by thinking of it)? And if in any degree you experience yourself as a creator of your experience, or even to some degree as the owner of your perception of your experience, then how can you ever lack for anything? Merely considering something to be so is the useful original fiction that (in my experience, at least) begins to bring things into being over time (in a time-based, or time-considering) universe.

Therefore, putting aside definitions (i.e., disregarding the above and that we are likely talking about experience that is, hypothetically at least, completely unshared), it's okay to simply consider the quality of dignity to be restored. Allow the "untruth" of that to coexist with the "truth" that it has been lost--for just enough "time" for the possibility to begin to manifest in your experience.

We are really talking here about invoking the power of context. (Another dialogue, another day.)