質問: what does あちゃ...やっぱ頭打っちゃってるなーコレ mean? what does あちゃ...やっぱ頭打っちゃってるなーコレ mean?
回答: it depends on the context, but i imagine it means you/they must be really stupid or awful or crazy. the meaning of the sentence itself is “omg i/you must have hit my/your head”.