Is there anything I can do while frozen by Mei?

Once you're frozen, you just have to hope someone else distracts her before she kills you. It is possible to be bubbled out by a friendly Zarya, but that's not under your control.

Anyone with an invulnerability (Reaper's Wraith Form, Zarya's bubble, Zenyatta's Transcendence) can still escape while being slowed, if they activate the ability before the full freeze takes effect.

As of my knowledge from beta there is nothing you can do to break free from her ice other than waiting or dying.

As of Today i did not find any changes in Patchnotes so i assume there is nothing else to do.