Having lost four of five, the Nets have a bunch of problems, but Deron Williams isn’t one of them. The star guard, who has battled injuries all season, detoxified his body during the All-Star break last month and has been red hot since. He has lost weight, has more energy and spring, and says he finally can dunk again — even if he’s scared to try. During the week when Williams was sidelined with inflammation in both ankles, he did a three-day juice cleanse that removed toxins from his body and gave him energy. He also received his third round of cortisone shots and PRP injections, and the results have been both successful and dramatic. “My ankles don’t hurt,’’ said Williams, whose Nets play the Bobcats Wednesday night at Charlotte. “We finally got the injections in the right spot, and I feel a little bit better. I can actually go up and down stairs. I can run around with my kids. I can go to the playground with them. I don’t hurt every time I take a single step, so yeah, I feel a lot better.’’ In the seven games he has played since the All-Star break, Williams has averaged 21.7 points and 7.1 assists, shooting 45.5 percent from the 3-point arc and 89.5 percent from the free-throw line. And perhaps most telling? “I can dunk,’’ confirmed Williams, whose only attempt of the season came on Nov. 23 in Los Angeles, when he got emphatically rejected by Clippers forward Blake Griffin, fell and hurt his right wrist. As for when he’ll try again in a game, he said, “I don’t know. I’m still nervous.’’ Williams, 28, dislikes discussing his health and hates talking about his weight. “I’m glad you guys are concerned about me. It means a lot,’’ he said sarcastically.