It seems from the history that your 7 months old kid has redness
of the eyes. The common causes for redness of conjunctiva
are various types of conjunctivitis. Only few varieties are infected types and these respond to antibiotic eye drops like tobramycin
which you are using.
The varieties which are associated with nodule or bump over the conjunctiv aare usually allergic conjunctivitis
or Phylectenular conjunctivitis
which require other drugs along with or without antibiotics.
I advice you to consult your eye doctor for follow up and do enquire regarding these conditions, he will be able to diagnose correctly and advice or alter the treatment.