You have just had a first hand experience of the side effects of a topical application of garlic to your face and this is a typical reaction to the active ingredient in garlic, allicin. You need to stop applying garlic to your face, as acne cannot be reversed by the use of garlic. The only time that garlic is useful as a topical application is when you have an infected wound that has to be disinfected. For acne, there is a variety of other treatments that you should look into.
Acne and pimples are not a skin infection but a result of the sebaceous glands producing so much sebum that collects in the pores when they are blocked. The way to stop acne and pimples is to keep your pores clean and open so that the excess sebum that is produced is eliminated out of the skin and does not pool below the surface of the skin. Bacteria plays a role in the formation of a pimple but this is only after the accumulation of sebum, after which the bacteria cause an infection that results in pimple formation. Therefore, when treating acne, you should be treating the root cause. Pores of the skin are regularly blocked by oil on the surface of the skin as well by its own dead skin cells. Skin sheds off very often and you have a new layer of skin on your face almost every three or four days. With so much skin coming to the surface and being brushed off, some cells block the pores and cause acne. What you need to do is to keep this dead skin off your face.
Exfoliation is the mechanism of choice to remove dead skin. What you need to do is to get a face wash containing salicylic acid. Salicylic acid is related to the active ingredient of the analgesic, acetylsalicylic acid. This acid is powerful and can work on the skin by breaking down the protein structures of dead skin cells. This makes it easy for removal. Apply the preparation on your skin and then with a preparation of lemon juice and sugar crystals, rub your face as if you are trying to sandpaper it. This will remove the layers of dead skin from the face. Wash this off immediately and to open up your pores that may already be blocked, stand over some boiling water and let the steam waft over your face. You will immediately start sweating, forcing out any buildup up of dead skin and dirt in the pores leaving the sebaceous glands free to produce as much sebum as it wants and not clog to form pimples.