I remember reading a book years ago about a young man or boy with a bad arm or hand moves somewhere new(I think different country) finds a some thing that transports him to a new(alien) world.
Other details I remember are, on the alien world he meets a girl(not necessarily completely human).
In the first few chapters the young man or boy with a bad arm or hand, filled a cake with laxatives that was eaten by the apartments building owners kid
The young man was also accompanied by another young man or boy he just met to the other world.
I remember in the next book the alien girl comes with them back to earth and the government sends agents to investigate the thing that transported them to a new world.
The alien world I think was having a war.
Thank you any help.