There's no praise, but plenty of self-promotion.
Fox San covered his face at the sound of it, deciding not to mention any more. His cultivation days were unbearable to look back on. Barring extreme circumstances, he would not let Fox Er literally kill him with intensive training.
Moreover, Fox Er's manoeuvring had tremendously advanced his level to Innate Great Perfection, but building up one's magical powers wasn't an overnight achievement. Fox Er had no better solution, so he used a simple and rough method favored by doting parents: he forced open his mouth and poured down dozens of elixir potions.
The medicinal power melded into his flesh and blood, but the refining process would take some time. Currently, his level and magical powers were out of balance, which was undoubtedly fatal for a magician.
So it's better to stop while he's ahead than to boast further. If Lu Bei challenged him to a duel, he would undoubtedly be exposed and ridiculed.