Girlfriend pregnant ?: engaged in protected sex and ejaculated on her buttcheek but as i did i noticed sperm getting in between her ass crack and wiped it away from the direction of her vagina and used tissues, whats the chance of pregnancy?

From what you described the risk of pregnancy is low. If your GF misses her period by 4-5 days, she should do a home pregnancy test. If the result is negative repeat the test 4-5 days later unless you get a period by then. Use first morning urine and follow the instructions carefully. Safe sex: https://www.hopkinsmedicine.org/health/wellness-and-prevention/safer-sex-guidelines