Thank you for posting. You do not need to worry about this. It usually takes around 7-9 days for a viral illness to settle. If other family members also had this problem most probably it was a viral illness. Viral illness are self curative and there is no need for antibiotics to treat them. It is very usual for a child suffering from a viral respiratory infection
to get loose stomach as well. specially towards the end of the disease. It is called a stomach flu
. body rashes like the one you have explained can be a result of this viral infection. So I do not see a reason for you too be worried. Keep your Boy well hydrated. Try to give him soft diet
, the ones he likes to eat. Try using ORS
reagent, you can make this at home. Use 1liter of boiled water, add 2 teaspoons of salt with 1 spoon full of sugar. this will take care of his energy requirements and body salts, which he will be loosing. Use this is small amounts on multiple occasions. Do not stop giving him milk, if he is taking mothers feed, carry it on but take special care of cleanliness.
Keep an eye on his temperature and those spots, if they start to increase in number or size please see a doctor.
Secondly i would like to tell you that use antibiotics with care. and use them when absolutely necessary. As extensive use is causing resistance.
If you have any more questions. Please feel free to contact me. Take care of yourself.