You may chose to pardon the annexation by passing a pardon through your officials. I may not issue a pardon for your independence. My Great Charter is not amendable except by any consequence of time, not specific event. If you want all of it back, however, you will have to purchase it at a sum of today's equivalent of 300 billion dollars. If you wish, Erinaum's high council will simply let you buy the land with fewer legal processes priced at modern equiv.: 4 trillion dollars.
If you wish, you may petition to become a protectorate of Erinaum until you get your country in order. We will leave your country and establish you as a sovereign nation once you are fully able to stand on your own. You may develop whatever governing system you like. (Basically, this offer is to allow Erinaum to occupy parts of your country and aid your it to develop to modern standards. You shall, in other words, be doctored back to health as a nation. (Starting too early might put you at the stability of Africa nowadays. This is a good offer.)