What do I have to do to call this events to be display on the web page?

Question

How do I call showLottery to display on my webpage?

Front-End

class App extends React.Component {

  state = {
    address: '',
    lottery: '',
    events: '',
  }

  async componentDidMount() {

    await window.ethereum.enable()
    this.w3 = new Web3(window.ethereum)
    const address = (await this.w3.eth.getAccounts())[0]
    this.setState({ address })

    this.contract = new this.w3.eth.Contract([
      {
        "constant": false,
        "inputs": [],
        "name": "implement",
        "outputs": [],
        "payable": false,
        "stateMutability": "nonpayable",
        "type": "function"
      },
      {
        "anonymous": false,
        "inputs": [
          {
            "indexed": false,
            "name": "_lottery",
            "type": "uint256"
          }
        ],
        "name": "showLottery",
        "type": "event"
      },
      {
        "constant": true,
        "inputs": [],
        "name": "num",
        "outputs": [
          {
            "name": "",
            "type": "uint256"
          }
        ],
        "payable": false,
        "stateMutability": "view",
        "type": "function"
      }
    ], "0xF666108e057d5CA30a962eEf43Ef25ff52b70364")

    const lottery = await this.contract.methods.num().call()
    this.setState({lottery})


  }

  async randLottery() {
    await this.contract.methods.implement().send({from : (await this.w3.eth.getAccounts())[0]});
  }

  render() {
    return (
      <div className="App">
        <p>Address KUU: {this.state.address}</p>
        <button onClick={this.randLottery.bind(this)}>Rand</button>
        <p>Lottery Number: {this.state.lottery}</p>
        <p>History Number: {this.state.events}</p>
      </div>
    );
  }
}

Smart Contract

contract testRand {

    uint256 public num;

    event showLottery(uint256 _lottery);

    function rand() private view returns (uint256) {
       return uint256(keccak256(abi.encodePacked(block.difficulty, block.timestamp, now , block.coinbase)))%(10**6);
    }

    function implement() public {
        num = rand();
        emit showLottery(num);
    }

}