How dangerous can be oral sex?

Last month I had sex for the first time in my life with a prostitute. I used a condom and I went down on the prostitute and had oral sex. I was worried about that oral sex I had.

What are the chances of contracting any disease because of that oral sex? How many months should I wait to go and get my check up done? Please suggest your valuable opinions. It would be a great help.

Thanks.