Hi, My Toddler Was Sneezing Continoualy Yesterday And Her Nose

Hi,

My toddler was sneezing continoualy yesterday and her nose was runny.. however it reduced to a large extent now.. we had our room painted day before yesterday? Could it be due to paint allergy? Will the allergy symptoms show up immediately or will take a day's time.. my two year old has never had cold till now.. I'm just worried if she has ingested any foreign body as she has the habit of mouthing whatever she picks up... would foreign body stuck in throat cause sneezing and runny nose... I'm a paranoid mother and have subjected her to 2 unwanted x rays to rule out battery ingestion so I don't want to go through another x ray.. I want to know what would be symptoms of any foreign body like metal or plastic when stuck in throat... she was having corn yesterday... if she had inhaled a corn granule through her nose would it pass beyond and would she be acting normally.. since today morning she sneezed only thrice... if at all it was common cold can it get better in a day... how would i know if it was a foreign body ingestion or allergy or a viral? What would be the symptoms for each one?