1. not at all
2. not at all
3. not at all
1. Should I be worried about HIV
No, there is no risk for HIV from this. HIV is only a risk from unprotected penetrative vaginal or anal sex.
2. Should I be worrried about stds and how soon should I get checked?
No, a brief lick isn't going to transmit any STDs. You do not need to test.
3. I immediately came home and showered and wiped my penis with an alcohol pad thinking this might help, should we not put alcohol or peroxide on penis area ?
No, this can be irritating to delicate skin, and won't prevent anything. Once you're infected, you're infected.
4. Are there any vitamins or over the counter stuff to take that can help with prevention?
No. If your immune system is healthy (and by healthy we mean not immunocompromised, like with AIDS, undergoing chemo, etc.), you do not need to do anything else.
The only thing you can do to prevent STDs is abstinence, or condom use. Condom use prevents infections like HIV, gonorrhea and chlamydia when having oral sex or penetrative sex, but don't offer full protection against things like herpes, hpv and syphilis.
Again, though, you aren't at any risk from this encounter.