My emphasis was that there is no measurable risk; you're putting a negative spin to say "So there is a small chance". There are no guarantees; nobody can say it is impossible you were infected. Someday you also might be hit by lightning; the chance of that is higher than the likelihood you caught HIV.
Dried secretions cannot transmit HIV.
Please accept the reassurance. Get tested if you must, but you really shouldn't be having second thoughts about HIV in this situation. It isn't a realistic possibilty.
So there is a small chance, if he is infected that he may have passed it on to me, by this activity? I think by the time he touched me down there, the ejaculation fluid had dried off in his hand. Does this lower the risk?
Welcome to the forum. Bottom line: Very low risk for HIV and other STDs.
Assuming your partner is not at particularly high risk for HIV -- not bisexual, a needle-sharing drug user, formerly imprisoned, nor immigrant from a high-AIDS area (like southern Africa) -- the chance he is infected is very low. Even among the most promiscuous heterosexual men and women in the US and other industrialized countries, on average fewer than 1 in 1,000 have HIV. If he is African American, especially from an inner-city background, the risk is higher -- but still the large majority are not infected.
When a man has HIV, the average transmission risk to female partners is once for every 1,000 episodes of unprotected vaginal sex. There are no data to calculate the risk for genital apposition without penetration (or for external genital contact with pre-ejaculate fluid), but the risk has to be very much lower than insertive sex with ejaculation. It may be truly zero risk.
So considering both the low chance your partner has HIV and the low likelihood of transmission if he is infected, the chance you caught HIV is no more than 1 in several million -- low enough that you don't even need HIV testing. That's from a risk assessment perspective; you might still want to be tested for the anxiety relief you can expect from a negative test result, which might be more effective than my assessment.
I hope this helps. Best wishes-- HHH, MD