Bit by small dog on outer thigh. chihuahua on leash got away from my neighbor. didnt think to ask about vaccines. wealthy neighbors dogs look well cared. dont think it broke the skin, it looks like a scratch, should i worry? southern usa?

Keep it clean. Insure your tetanus is current, with 10 years. If it did penetrate the skin, an antibiotic is often indicated. For sure if you experienced redness or swelling or your body becomes otherwise sick, such as fever.

In addition to Dr. C's good advice, you should be quite reassured that that dog has been vaccinated for rabies prevention if your neighbors are solid responsible people.