hello, about 2 weeks ago I was doing some sanding on wood and mdf, i stupidly didnt wear a mask as I only expected to be doing it for 10-15 mins, anyway i have had a chesty cough for 2 weeks now, and each day will have several episodes of intense coughing fits, but I am unable to cough any phlegm up. how long should I expect this to last before my body is back to normal, or should I go to a GP to get myself checked out