I have a scratchy and very irritable eye. noticed there is a small "pimple" on the inside of my eye. my eye has since turned red. what could this be and which medication is best to use?

May not need drugs: You may have a stye (infected eyelash follicle), but from the redness and itching you describe you may instead have a conjunctivitis ("pink eye"). Another possibility from your description would be a chalazion (blockage in oil gland). Stye and chalazion require minimal treatment. Warm water compresses usually help. Conjunctivitis sometimes requires antibiotics, but often improves without them.