what did Derry's mother think of Mr. Lamb?

When Derry entered the garden, he was full of negativity. He entered thinking it to be a secluded place. The minute he saw Mr Lamb, he felt uncomfortable as he didn't like anybody's company. He thought people must be afraid of his acid-burnt face. Moreover, he himself was afraid of his face. He had a preconceived notion that people would call him ugly, terrible and scary.