Sexual concerns and virginity

Given the data you provided (inserting tip of the penis slightly without using condom, your partner being virgin penis became flaccid (soft) when pulled out) you might have lost the erection simply because of the unpleasant situation.

Nothing you mentioned indicates that the penile tissue was damaged.
Since you did not ejaculate, the chances for her being pregnant are very low, but not completely eliminated. The pre-ejaculation fluid (precum) might contain viable spermatozoids, especially if ejaculation occurred within a few hours earlier.

If your girlfriend misses her menstrual period you might want to suggest that she visit a gynecologist for a physical examination, hormonal laboratory tests and an ultrasound scan to determine whether she is pregnant or not. The gynecologist might also provide suggestions about available contraception options.