Your
beta hCG being negative more than two weeks after this contact is a reliable result for you. External touching without penetration carries very low risk for you in the first place.
Next Steps
If your next period doesn't start on time, repeat a home
pregnancy test after a week. Since your periods run irregular anyway, track your cycle length from here on.
Health Tips
Please get a gynaecologist opinion if your irregular cycles continue beyond a few months.