You get over a relapse by getting straight back on low carb/keto. You can also try drinking an extra 2 glasses of water.
Snacks will fade over time but initially try:
A spoonful plain full fat greek yoghurt, sipped slowly off the spoon. Then walkway from the fridge for at least 30 minutes.
A small handful nuts, plain, unsalted.
A square or 2 of at least 85% dark chocolate.
Cheese slices ,microwaved into cheese crisps
In each case snack, then walk away. Do not take food out of the kitchen. Most times you won't need to go back again.