Hello, Although implanon is not approved to be used for more than 3 years but the fact is that it doesn t stop working in three years. So if you are worried about it s contraceptive efficacy,you may use an extra backup contraceptive till you get it replaced. Sometimes imlanon  removal becomes difficult because it goes in deep or gets encased in fibrous tissue or may even migrate. Sometimes,too deep insertion may cause some nerve damage and may result in paraesthesia,but there is nothing to worry. This is just normal and would become allright,once it is removed in another few days. Sometimes a lady may feel the paraesthesias more because of subconscious presence of implanon beyond it s usual duration. There is no harm,if it stays there for few weeks more. Thanks