Yeah, I think about the only place a Mediterranean House Gecko could bite a person might be the fold of skin between the fingers, or someplace similar. They're not very large lizards, probably not even as large as the Carolina or Bahama Anoles.

I'm not sure if the larger geckos could actually break the skin, though even if they could, I doubt their bite could be worse that a ball python bite. If they do break the skin, clean it well and put some neosporin or similar anti-biotic cream on it.