He may continue teething or a tooth may pop out. If he's still biting down on things, it sounds like he's still teething. I've been told and have read that when babies get their teeth it's hereditary. Do you know when you and your husband got your first teeth?
My son is now 8 months old and he also started teething at 4 mos (tons of drool, chewing, crankiness, etc..) but he didn't get his first tooth until 7 months. He had a bump in his gum for 1 month. He just now got his second tooth at 8 months. I gave him Hyland tablets and gel and sometimes Tylenol when it was really bad. I also gave hum Hyland colic tablets which are basically camomile. He loved all these tablets. He hated baby oragel - gagged and cried so we didn't do that. A few times, he'd wake up crying in the middle of the night and the poor little guy would be wimpering while chewing and drooling all over his sleeve. We'd comfort him until he'd fall back asleep & give him Tylenol. For him, teething has been intermittent - some days & nights are really bad and some days nothing. The pain and discomfort comes and goes as the teeth are moving. Try different things to chew on - wood toys, cloth toys, rubber toys. My son likes warm washcloths. He wasn't fond of frozen things but we tried frozen mini bagels, frozen wash cloths, frozen gel teething toys. His absolute favorite thing is a Nuby - it's a hand held teether with a small mesh bag - you can put teething biscuits, ice, apples, whatever in it for baby to chew on without choking. You can hand wash in in hot soapy water or put in dishwasher. He LOVES chewing on a teething biscuit in it - he also loves chewing on the handle. Best $6 we ever spent but we wished we had bought it sooner. We bought his at the Right Start but I've seen them at all baby stores. Re: the crankiness, you have to just go with it and comfort him as much as you can. We found that taking him for walks (either in stroller or carrier) late in the day was a life saver.