cylinder head

Hi to everybody,never been in a forum before or posted a thread either,probably not had much to say,.....until now perhaps! I have a gorgeous M750 called Ruby,previous owner put all her docs,cd,etc into a folder with her name on it,so I cant change that now! Never got out on her last year due to health and crap weather. The new battery which I thought was only bought last year,turned out to be nearly two years old and goosed! Yesterday when taking out the old spark plugs,the bottom one came out and the new one went in fine,the top one or rear head one was only partways in and tight to come out,like i've put it in so far cross-threaded and stopped,probably from two years ago eh,plonker! I'm lucky I have a McConechy's literally two minutes from me,and the guy there is a wizard on bikes etc,I'm sure it'll all be sorted in the end but i just wondered if I did need a new head,or replacement,maybe someone here has had a similar experience and could pass on some valuable thoughts,info or anything,many thanks