I'm 18 years old and panicking. I don't want to be pregnant.
It would be very unlikely for you to have become pregnant if you have not had full sex.
If your boyfriend ejaculated in the genital area there could be a remote chance but very unlikely. It would be worth ringing the national helpline and speaking to a trained advisor so that you can explain exactly what happened.
Please don't feel embarrassed or 'silly' we have had others who have asked a similar question about getting pregnant without having full sex. You may have been feeling anxious and that could affect how you felt physically.