teething advice?

my baby is just over four months old and he’s teething so badly. he’s constantly got flushed cheeks, chewing his hands and cries for hours and i can’t seem to soothe him, what can i use to help him? he’s good with teething toys but when im trying to get him to sleep they just keep him awake. i know a lot of gels can be only used from 5m+ but can i give them to him now?