Hello Ma'am, you did the right thing by asking the question. I will try to equip you as best I can.
First of all, Vicks BabyRub is not a first choice of treatment,due to its low efficacy and possible side effects, especially via skin and nasal irritation. Also, while the company recommends safe use from the age of 3 months, contact with the eyes and mucous membranes should be avoided, which can be difficult to control at this age.
So, if the child's only symptom right now is coughing, there's nothing to worry about. Know that this is a natural mechanism of the body to remove respiratory irritants. For example, secretions from the nose into the throat can cause this cough reflex. If the cough lasts longer than 3 weeks, however, it would be appropriate to consult a physician to explore the underlying cause.
I hope I have equipped you well for the next steps.
Maeva Di-Re, Pharmacy Student
Supervised by Alexandre Chagnon, Pharmacist