2 yr old teething problems

My son is having teething problems. He's almost 2 and according to doctors, mothers etc he's having slow teething. Recently it had become so horrible that his gums became blue/purple. took 4 mths for him to take those 2 teeth out. even for other ones he takes much longer than I have seen with other kids in his playgroup.
As such he seems quite normal i.e playful, doesn't cry too much. He does have restless sleep and wakes up to the slightest noise. One thing which really stands out is that even in winters actually specially when it's cold when we take off his socks/or gloves his hands and feet start sweating.
I thought about Merc. Sol but wasn't sure.
Thanks in advance