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Due to raw surface of circumcision
a serous exudate is expected for a day or two but day four means there may be a problem related to local infection, and if that is the case can cause scarring and bending of penis shaft in long run.
Please review to your surgeon, I think slight local care and dressing and an antibiotic is all that is required for some time.
I hope this advise would be helpful for you.
Still if you have any queries or doubts, please write me back,
I would be happy to solve them.
Wish you a great health!