You can stop doing your activity until the blister go away. It’ll get worse if you continue. You can stop wearing the tight shoes that you’re wearing. Just wear sandals without the back and give your foot a rest.
You can poke the water bubble with a needle and then put antibiotic on it so that you don’t get an infection. You will then cover it with a bandage or a gauze so that you don’t get infections to come in. You don’t allow bacteria to come in.
Allow it to sit for about a week and it’ll heal. You can change bandage or gauze as needed. Don’t put anything dirty on top of it and don’t touch it. It can be painful if you try to touch it. Use an ice pack to relieve your pain.