Our daughter had great difficulty falling asleep and we went to a naturopathic doctor who recommended children's liquid melatonin. It tastes good too. We ended up trying a combination of things, so I'm not sure exactly what worked best. But melatonin was part of it.
My Toddler has Insomnia - Page 2
OP - how are things going?
I'm hesitant to type it, but things seem to be going ok here. We've moved his bedtime up and his wake time, and he's napping more consistently (instead of dropping naps here and there). We modified his bedtime routine by watching all the things he did AFTER he climbed out of bed in a frantic state (we realized he needed a bedtime snack, some water play, some quiet play with trucks in bed - and a new goodnight book about trucks helped alot, too!).
I still think alot of it is also teething/developmental, but hopefully we are in for smoother sailing (fingers crossed!).
Hope you've found some tools that work for you!