Brief Answer:
Could be because of coughing

Detailed Answer:
Hello

Thanks for the query

Abdomen can turn black and blue due to coughing, it is because of bleeding under your skin.
All coughs lasting for more than 1 week should be evaluated. This is how you should go about it

1. Get a chest x ray along with complete blood count done
2. Send sputum for gram stain and culture
3. I recommend that you start antibiotics. Tab Cefixime 200 twice daily for 5 days is what I write
4. Levocetrizine twice daily with cough syrup like ambrolite s three times will help with the cough and cold
5. Avoid cold food and beverages
6. Avoid smoking, milk and milk products.

I hope I was of help, if you have any further queries please get back to me

Regards

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