Blocked Nose!

My 7 month old son has had a blocked/stuffy/runny nose for over a month now. We have been back and forth at the doctors who simply advise that it’s a cold and he’ll get over it.. my last visit I suggested to the doctor that it could very well be allergies as he sneezes and rubs his eyes etc. We’ve now been on allergy meds for a week now and his nose is dried up (rather than running) but still very congested higher in the nose.

We have tried sitting him in the shower with steam, vaporisers, saline sprays, nose suckers.. I am at a loss at the moment and not sure if anyone has had a similar situation and what you did to ease it?