Thanks a lot for the info！

No, it is not wrong to end a sentence with a period and then start the next sentence with “however.” When you have two closely related independent clauses, you can use a conjunctive adverb like. “; however, ” to bridge the two sentences. I think it’s preferable to use the latter when the sentences are very closely related and you want to keep the flow of the sentence.

Jon Hanna provides an excellent answer to this. I'd suggest reading his comment on 'however' if you want a detailed explanation. You can find his answer here: https://english.stackexchange.com/questions/104864/use-of-a-semicolon-before-and-comma-after-however