Howe has admitted he's felt let down by the Swede over his behaviour over the summer.
Speaking from the Sweden training base, Isak said: "It's nothing I want to dwell on now.
"It doesn't benefit anyone, neither me nor Newcastle so let it be."
Asked if he has spoken to Howe since he left, Isak replied: "No.
Unless the two sides draw each other in the FA Cup, Howe and Isak will not reunite until Newcastle travel to Anfield on January 31st.