The noun humiliation can be countable or uncountable. In more general, commonly used, contexts, the plural form will also be humiliation. However, in more specific contexts, the plural form can also be humiliations e.g. in reference to various types of humiliations or a collection of humiliations.

What is the plural of shame?

The plural form of shame; more than one (kind of) shame.

Can the word my be plural?

The plural of “my” is “our.”