Answer by taking a quote from the following article:

Field Marshal Henry William Paget, 1st Marquess of Anglesey,  (17 May 1768 - 29 April 1854), styled Lord Paget between 1784 and 1812 and known as the Earl of Uxbridge between 1812 and 1815, was a British Army officer and politician. After serving as a Member of Parliament for Carnarvon and then for Milborne Port, he took part in the Flanders Campaign and then commanded the cavalry for Sir John Moore's army in Spain during the Peninsular War; his cavalry showed distinct superiority over their French counterparts at the Battle of Sahagun, where his men captured two French lieutenant colonels and so mauled the French chasseurs that they ceased to exist as a viable regiment. He also commanded the cavalry at the Battle of Benavente, where he defeated the elite chasseurs of the French Imperial Guard.

During the Hundred Days he was appointed cavalry commander in Belgium, under the still resentful eye of Wellington. He fought at the Battle of Quatre Bras on 16 June 1815 and at the Battle of Waterloo two days later, when he led the spectacular charge of the British heavy cavalry against Comte d'Erlon's column which checked and in part routed the French Army.  One of the last cannon shots fired that day hit Paget in the right leg, necessitating its amputation. According to anecdote, he was close to Wellington when his leg was hit, and exclaimed, "By God, sir, I've lost my leg!" -- to which Wellington replied, "By God, sir, so you have!" According to his aide-de-camp, Thomas Wildman, during the amputation Paget smiled and said, "I have had a pretty long run. I have been a beau these 47 years and it would not be fair to cut the young men out any longer." While Paget had an articulated artificial limb fitted, his amputated leg meanwhile had a somewhat macabre after-life as a tourist attraction in the village of Waterloo in Belgium, to which it had been removed and where it was later interred.  Paget was created Marquess of Anglesey on 4 July 1815. A 27-metre (89 ft) high monument to his heroism (designed by Thomas Harrison) was erected at Llanfairpwllgwyngyll on Anglesey, close to Paget's country retreat at Plas Newydd, in 1816. He was also appointed a Knight of the Garter on 13 March 1818 and promoted to full general on 12 August 1819.

What did he do after his leg was amputated?
While Paget had an articulated artificial limb fitted, his amputated leg meanwhile had a somewhat macabre after-life as a tourist attraction in the village of Waterloo