No, the only times it can be fixed is DCing and rejoining unless it's VERY bad and even that isn't permanent, it will start to slow down again after a bit
For some months now (before the first 6 new heroes patch) I've been dealing with a problem where at the start and for about 1/3 of a match my game will run smoothly with no problems but then, at some point (I haven't been able to pinpoint a specific thing that would cause this), the game will...