7 1/2 month old with hoarse voice?

I have a DS who is 7 1/2 months old. He has had a cold for almost 2 weeks. I took him to the Dr a week ago and they said his oxygen level was 100% and he was not congested except for a little bit in his nose which was probably coming from teething. He was coughing a little then and has the same cough now...not worse. The Dr said because he is in daycare it could last up to a month for it to completly go away. Over the last 3 days his voice has started to go hoarse. he is eating great (we actually have had to up his formula ounces and he eats solids 3 times a day), playing fine, sleeping like normal and hasnt been acting anything out of the ordinary. Should I be worried about the hoarse voice?