To convince the client, he practically talked himself hoarse.
Tips
memory
Picture it literally: 磨破 (mópò, 'to grind through') + 嘴皮子 (zuǐpízi, 'lip-skin') — talking so much you wear holes in your own lips. Vivid and easy to remember.
register
Colloquial. Always carries a tone of frustration — the speaker tried hard and still failed.