I'd recommend speaking to your pharmacist as they will be able to recommend an OTC remedy that you will be able to use.
These remedies usually contain salicylic acid which dissolves the verruca, a type of wart, and they come in a cream or ointment which is applied directly to the wart but there is also a form of treatment which freezes the wart using a very cold spray.
You might also be interested in a DIY treatment option which involves covering the wart with duct tape or bear tape so it is much less expensive than the OTC remedies.
You place a piece of tape over the wart for 6 days, if it falls off you just replace it with a new piece of tape. At the end of the 6th day you remove the tape and soak the wart in water. You then use an emery board to rub the wart and leave it uncovered overnight. The next morning you place a piece of tape over the wart and start the process over again. This cycle is repeated again and again until the wart has gone.