Use a bar of soap and wash your penis after a session. Do it at the premises if possible. If not, do it as soon as you get home. Simple surfactant - the ingredient that makes soap clean your skin - is sufficient. You don't need anti-bacterial creme or anything of that sort.
Hookers aren't as dirty as most people imagine. They aren't infested with disease and viruses. I have eaten from the same plate as a hooker, shared utensils, gotten 100s of BJs, I even helped put a bandaid onto a hookers finger that suffered a cut when we were out together. I didn't think anything about it. I didn't worry. I didn't run to the clinic to get tested.
Hookers who routinely offer anal with be higher risk for you because they are more likely to get infected, although I think the infection rate is still very low. Trannies are the same. Fat escorts and those that do BDSM would have more extensive menus and have a higher risk of infection too, although still very low. Just wear a condom if you are going to do anything other than a BJ.
Only worry about the hookers who do BBFS and the clients who brag about it. Try to steer clear of that. You can get a BBBJ or a CBJ (both are safe) and if you are going to have vaginal or anal sex, use a condom. You will be fine. I don't normally perform DATY on an escort, but that is simply because of the volume of men she may see each day. Nothing to do with disease, just not something I want to do when the last 3 guys that same afternoon also did it for her as well. Just a gross-out factor, not a disease or virus concern on my part.
If you are going to rim an escort, use a mouthwash immediately afterwards. If you don't, decent chance you will eventually get strep throat (if you repeatedly do it enough). Fecal matter isn't clean and God didn't intend humans to lick each other's anus.
I am a hypochondriac. I started visiting whores to overcome my hypochondriasis. It worked in the sense that I don't fear anything when I am with an escort, but in my day-to-day activities outside the hobby, I still get nervous when I touch door handles or eat at restaurants etc.