Do not blame yourself as bullying is about power
People who bully target tend to be sensitive people who are likely to attack themselves in response to shame. Self-blame can maintain a relationship with a bully, but it comes at the expense of keeping oneself a victim.
It is important for the victim to not start doubting his/her own abilities because that is exactly what the bully wants. The bully wants to intimidate the victim and be in complete control of him/her. Once the victim recognizes that he/she is being bullied, he/she can take the required action and inform HR, their supervisors, or their colleagues about the incidents of bullying and find a solution to the ongoing problem.