Thanks for query,
Your son has acute gastro enteritis
due to cleaning of the part repeatedly he developed rashes on the part.
Retraction of testicles are normal,nothing to worry.
But loose motions may produce dehydration
which may produce complication.
So it is better to take him to ER.Timely taken treatment prevents dehydration.
Meanwhile give plenty of water,lime water juice,electral powder.
Ok and bye.