Thanks for writing to DoctorSpring.com with your health concern.
Yes, as the condom was not used properly, there is a risk of pregnancy. You can take emergency contraceptive pills which are more than 80 % effective in preventing a pregnancy if taken within 72 hours.
Please take the Plan B one step as that will provide protection. Please remember that it is not a proper substitute for regular contraception.
It will induce withdrawal bleeding within some days. It may prepone or postpone your normal cycle by a week, or sometimes, even more.
All the best.
Please feel free to discuss further.