I've googled and found this:
"Antibiotics
What are antibiotics?
Antibiotics are a group of drugs which treat bacterial infections, ranging from quite mild infections to serious, life-threatening diseases.
Which antibiotics cause hearing loss?
The group of antibiotics that are most likely to cause hearing loss are aminoglycosides. These include gentamycin, streptomycin and neomycin. These antibiotics are often used to treat serious or life-threatening bacterial infections, such as tuberculosis (TB). They are sometimes prescribed when a bacterial infection does not improve with treatment using antibiotics which are not in the aminoglycosides group.
What are the risks of using drugs from the aminoglycosides group?
The risk of hearing loss from aminoglycosides can increase depending on the following factors:
how high your dose is
how long you take it for
whether you are given it by injection.
Some research suggests that some people are very sensitive to antibacterial eardrops. These can permanently damage your hearing if you have a perforated eardrum and the drug enters your middle and inner ear, especially if the drug is taken for a long time or in a large dose.
Aminoglycosides can also cause tinnitus, as well as hearing loss. If your problems are caught in time and the drug is stopped, the tinnitus will usually go away. In some cases the hearing loss can be severe, although this is rare.
If you are prescribed aminoglycosides, you should be aware of the risk of permanent damage to your hearing. The effects are usually monitored when you are in hospital, by regular blood tests to estimate how much of the drug is in your bloodstream. However, remember that aminoglycosides are generally prescribed to treat serious, life-threatening diseases, where saving your life is felt to be more important than the possible risk of damaging your hearing."
That's the bit that's most relevant to you. It doesn't say what the likelihood is - but it sort of suggests that eardrops are more of a problem, I think?