Technically you can get pregnant any time you have unprotected sex. *8 days before your period could be problematic and in the range of when you were ovulating.
If he just touched your vagina though, then I would not be concerned. A penis generally has to enter your vagina. I would say you are not pregnant.
The days you give with 8 days and 20th day and 26 to 28 days are hard to follow. good luck