There is very little risk of you getting an STI from this.
The only possibility is from giving her oral sex, and the chances are very, very low, if any.
Oral sex on a vagina is among the lowest risk, and since you only did it briefly, I wouldn't really even worry about it. Most experts don't think one act of oral sex warrants testing, and you barely did it.
Since she didn't have any sores, I see no reason to worry at all.