I have attempted 3 times over the last 8 months. Most recent I tried for 2 days. After 12 hours, intense  sweating, muscle spasms, anxiety, restlessness, yawning, eyes and nose running, coughing phlem. Lasted 2 days almost and used Kratom to help with symptoms. Relapsed after 48 hours. 

Withdraw Symptoms in the last few months begin as early as 4-6 hours. Cold Sweats as soon as 4 Hours. The recent Fentanyl switch has increased everything, and has made other opiod options almost absolute because of the strength. 