Depends where. Symptoms of bacterial infection very depending on the organ system involved, commonly including fever, pain and feeling under the weather. A urine infection presents with pain and itchiness with urination, a skin infection with redness and boils, a respiratory infection with difficulty breathing.
Depends on the bug. As dr evans described, the "where" is key to understanding an infection. Also, different bacteria do different things to the body. Usually, though, there is some kind of "-itis." dermatitis is "itis" of the derma or skin. "-itis" involves irritated or enlarged blood vessels, so these lead to redness, warmth, swelling, and pain or itch. Viruses can do the same, though, so not always easy to tell!