Recent episodes of low pitch tinnitus

After a month long battle with PET and PT I’ve been having more frequent episodes of tinnitus. These episodes only last a minute or so but are happening often and have only been a very low frequency ring. After the month long ordeal with my other ear and it not going away, I keep panicking when it happens thinking it may not go away. What could cause it to be such a low pitch and if the episodes come and go quickly, is it less likely it would stay?