Redness right after the test does not necessarily mean you have been exposed. Between 48 and 72 hours they are supposed to check for hardness, like a bump in the skin, not just redness. PPD tests cannot really be accurately read by just looking, it should be touched, unless there is absolutely nothingnthere and an obvious negative. However, if the irritation is getting large, you might want to report it to your doctor in case you are having a bad reaction.
If it winds up you are positive for exposure to TB, you should never get the skin test again. You will be positive forever, and it is contraindicated to have the test done, because reactions to the test can get worse and worse over time. You will be required to get a chest xray to make sure you don’t have active lung TB. You can opt to take antibiotics for exposure, it is not required, and the antibiotics are strong, and I think the regimen is 6 months, so it is a big committment. Most doctors won’t even suggest it to you. Two people very close to me chose to take the drugs, many people I knew who worked with me who were positive for exposure never even heard of taking antibiotics for it, and I worked at a behavioral hospital woth doctors all around.
If you actually have active TB you will be required to take antibiotics, and possibly might be monitored in some way for compliance. If you have no cough this is extremely unlikely.