Severe tongue bite due to parkinson's medication side effects - what can my mother use to fix her sore tongue?

A bitten tongue can exhibit lacerations or bruising. Take your mom to a Dr for a thorough examination. If the tongue has a severe laceration, it may need suturing/stitches. For bruising, cold fluids held in the mouth for several minutes can provide relief.

This should not be happening with Parkinsonian medications. Might expect this in a tardive dyskinesia instead, but excessive medication can create a dyskinesia instead of resting tremor. Are you sure diagnosis is correct? Should you seek a second opinion. Excellent advice given to treat tongue, but would hope to prevent recurrence.