can i pregnant by touching outside of vagina?

my boyfriend put his hand on my vagina.he didnt fingered me but maybe put his finger a bit near opening of vagina. the problem is that before fingering,he touched his penis though he didnt ejaculated. i fear that precum could be present on his hand. he told me he didnt touch the tip of his penis but still to be safe,can i be pregnant? this happen around mid december. i was on a diet in december and lost some kilos. i was size zero. i had to get my menses around 20-25 of december,but got it in 2 january.it lasted 2-3days. on first day,it was normal bleeding and then lighter for last 2days. i was also having nausea,but i thought it was maybe of diet and stop diet. on 5 february got menses but just 2days. first day,my pad was filled with normal bleeding and second day light pink blood. i took a hcg test around 2am after menses got over,it was negative. i am worried could i still be pregnant? please help doctor