Your risk was never existed. Therefore any test you go for, will always be reported Negative. HIV transmission is possible only due to exchange of body fluids INSIDE the body, not outside, so one has to have an unprotected penetration for HIV to transmit.
Your 50 days test was accurate and conclusive, and yes it is a 4th generation test and considered to be conclusive anytime after 28 days. You do not have HIV