He'll kythe in his ain colours yet.
"He'll appear without disguise; he'll be known for the man he is."—Jamieson.
He'll lick the white frae your e'en.
"This phrase is always applied when people, with pretence of friendship, do you an ill turn, as one licking a mote out of your eye makes it blood shot."—Allan Ramsay.
He'll mak a spune or spoil a horn.
"Ay, ay, we're a' subject to a downcome. Mr Osbaldistone is a gude honest gentleman; but I aye said he was ane o' them wad mak a spune or spoil a horn, as my father, the worthy deacon, used to say."—Rob Roy.
He'll mend when he grows better, like sour ale in summer.
"The young laird of Balmawhapple, ... he had no imperfection but that of keeping light company at a time; such as Jinker the horse-couper, and Gibby Gaethroughwi't, the piper o' Cupar; 'O' whilk follies, Mr Saunderson, he'll mend, he'll mend,' pronounced the bailie. 'Like sour ale in summer,' added Davie Gellatley, who happened to be nearer the conclave than they were aware of."—Waverley.
He'll need to dree the dronach o't.
He'll ne'er send you awa wi' a sair heart.